INTRODUCTION
The urgency of the subject
Everyday life is filled with a wide range of plastic products, from basic items like wash basins and combs to more complex goods such as phone cases, motorcycle parts, and computer components.
The ongoing advancement of the plastic industry relies heavily on the essential development of the molds industry A robust molds sector enables the diversification of plastic products available in the market, reduces production costs, enhances competition among companies, and provides consumers with a wider array of product choices.
The machining and manufacturing of plastic materials in my country is experiencing significant growth and development, keeping pace with global trends The machinery and equipment used in this industry are continually being enhanced Currently and in the foreseeable future, the plastic materials sector is poised for long-term growth, making it a promising strategic focus.
Because of these reasons, our group decided to choose the topic: “Design and Manufacture 6 Difference Spoons by Plastic Injection Molding”
Through this project, my group hope to apply the knowledge learned in manufacturing practice, contributing a small part to the development of the plastic mold industry.
The scientific and practical significance of the topic
Scientific Meaning: Using the knowledge of plastic injection molding goes into the study to design an effective mold.
Practical significance: the topic not only contributes to creating a low cost product, create new style but also helps consumers have more options to buy products, increasing the business competition.
Target of the topic
Study theoretical basis and flow analysis in plastic injection molds
Complete product design and mold design with support software
Manufacturing plastic molds for design products.
Research Methods
Survey the types of spoon products in the market and using demand, formulating ideas for the design of the product to suit the intended use
Refer to the template documentation Knowledge that has been accumulated References are collected through books, textbooks and on the internet
Use PTC Creo Parametric 3.0 software to design the product and take the next steps such as mold extraction, analysis, Mold design for the product
Find out the parameter and characteristics of the material that the business requires to design the mold properly
Use Moldex 3D software for flow analysis and injection molding
Use CNC machine to manufacturing mold.
Structure of bachelor thesis
Creative idea for product and design product
Simulate cases of runner system and cooling channel by Moldex 3D
Calculation parameter of mold and after that design the mold
Creative schedule operation to make the mold then manufacturing
OVERVIEW OF INJECTION MOLDING TECHNOLOGY
Products of injection molding technology
Injection molding technology produces a wide variety of plastic products in shapes and sizes that are attached to our lives
Create complex shape products in all areas of life: consume, food technology, healthcare, high technology
The product after injection has various colors, no need to paint
High gloss surface should not need to re-process
The products of injection molding technology are flexible, tough, light, diversified, eye-catching, human friendly Can be recycled to save materials
Sorting injection molding machine
2.2.1 Sorting machine by material used
Thermoset resin injection molding machine
2.2.2 Sorting machine by clamping system
The machine uses hydraulic clamping system
The machine uses the elbow gripper system
2.2.3 Sorting machine by clamping force
2.2.4 Sorting machine in the direction of screw
2.2.5 Sorting machine by injection molding technology
Thermoset resin injection molding machine
Materials in injection molding technology
Injection molding primarily utilizes plastic materials, which are synthetic substances derived from organic polymers When heated, these plastics become malleable and can be shaped under pressure, retaining their form once cooled.
Plastic materials used for injection molding are diverse with more than 20,000 thermoplastic and 5000 thermoplastic resins.
Fillers: in powder, fiber, organic, organic
Additives can also be added
Some commonly used plastic in the mold
Most of injection machines are suitable to use both two types plastic, thermoplastics: PE, PP, PC, ABS, PA, PMMA, PS, PVC, etc… and thermosets: PU,
PF, UF, etc to injection products as desired
The following tables describe the properties and areas of application of some commonly used plastics:
- Physical: white, slightly transparent, non-conductive electrical and non-conductive thermal, not for gas and water vapor permeable, brittle when exposed to sunlight
- Mechanical: PE is of low strength, hardness and rigidity, but has a high ductility and impact strength, low friction It feels waxy when touched
- Chemical: similar to paraffin, flexible, durable, and chemically resistant
- Optical: learn (transparent), milky-opaque (translucent) or opaque
- This material evolved into two forms, Low Density Poly Ethylene (LDPE), and High Density Poly Ethylene (HDPE)
- Matte and white, low temperature and low traction
- Easy to burn and smell paraffin
- High water resistance, chemical resistance, good thermal and electric resistance
- Large elongation and brittleness at low temperature, high expansion coefficient
- It’s primary use in packaging (plastic bags, plastic films, food packaging, intermediate bulk containers, pail, crate, bottles, etc.)
- Products used for insulation: conduit, insulation tape
- LDPE is used to make films and packaging materials
- HDPE is used for containers, plumbing, and automotive fittings
- Colorless, odorless, tasteless, non-toxic
- The lightest plastics with a density of 0.905 g/cm 2
- Stiffness, tough and flexible higher PE
- Heat resistant is better PE, good mechanical properties at high temperatures
- Brittle at low temperatures, degraded by UV
- Flammable, good electrical insulation, high frequency
- Impact resistance high, good resistance to fatigue
- Flow high, process ability good, injection or blow molding production process
- Widely used in the food industry: bottles, cling film, food preservation box
- Clothing: used in nonwovens, PP woven yarns, jewelry other wearable items
- Use chemical resistance: medicine bottles, thin film packaging, ducts,
- White or light yellow powder, not toxic, toxic only by additives, excess monomer
- Low heat resistance, low impact resistance, high hardness
- Good weather resistance, high durability, anti-aging
- Chemically resistant to acids, salts, bases, fats, and alcohols
- Used in sewerage piping, piping, flooring, gutters, decorative imitation "half- timbering", windows and doors
- Used for medium or low voltage and low frequency insulation materials
- PVC fabric used in coats, skiing equipment, shoes, jackets, aprons, and bags
Table 2.3: PVC (Poly Vinyl Chloride)
- Hard plastic, colorless, transparent, easy to color, no taste, amorphous
- Brittle, low strength, good elongation, poor impact resistance
- Cups, spoons, disposable plastic cups, baking trays, cream boxes, yogurt boxes
- Children's toys, clock face, electric meter, motorcycle cover, TV case, etc
- High mechanical strength, able to withstand tearing force and impact, high wear resistance, high rigidity
- Waterproof O2 and CO2 better than other plastics
- When heated to 200°C or cooled at 90°C, the chemical structure of the PET circuit remains the same, the air resistance of the gas remains unchanged when the temperature is about 100°C
- Used as a bottle, bottle of pure water, carbonated beverage, plastic tray food
- In the field of textiles, PET combined with cotton
Table 2.5: PET (Poly Ethylene Terephthalate)
- White opaque, semi-transparent, high viscosity
- Hard but not crispy, resistant and tough
- The ability to withstand relatively good heat
- Insulating products in electronic and communication engineering such as housing and components
- Industrial products: helmets, toys, shells and details in cameras, office machines, keyboards
Table 2.6: ABS (Acrylonitrile Butadiene Styrene)
- High durability and hardness, good impact resistance
- Good insulation, good moisture resistance
- Good abrasion resistance, low coefficient of friction
- Rail rails, belt wheels, connecting pipes, rolling wheels, anti-abrasion cushion
- Bearing details, gear, pump details, parts in automobile production
- Transparent, tough, stable heat, stable size
- Impact resistance, tensile strength, high heat resistance
- Used in many electrical and electronic equipment
- Roofs, bulletproof windows, billboards, greenhouses, goggles, etc
Can form at normal temperature and pressure, good adhesion to metal and concrete, good stress and heat, good chemical and water resistance, good insulation
The aircraft parts, the outer coating of the hull, used as fiberglass and carbon fiber reinforced materials, as insulating material, glue, surface treatment, plaster, paint, etc
Elastic, high durability, toughness, chemical resistance and good solvent, tear- resistant, scratch-resistant and high abrasion resistance, impact resistance very well
Cable wrap materials, ducts, textile yarns, linings, floors, linings, conveyors, shafts and wheels, concrete pouring molds, plastics
2.4.Some failure on injection molding products
1 Air trap The venting system on the mold is not good.
Design ensures flow balance.The final filling area must be well ventilated with the open gas.
Reduce the spray velocity so that the plastic fills slowly and the air easily escapes
2 Burn Marks The bubbles that accumulate in the mold under high pressure and heat will burn to create defects
The plastic also burns due to pressure and high pressing temperature
Properly design plastic conduits to avoid overheating
Design products to avoid air traps
Reduced rotational speed of the screw and injection pressure
Reduce the temperature in the heating chamber and the nozzle
The product has many welding lines
Different shrinkage direction leads to cracks
Increase the thickness of the logical part
4.Splay Mix material irregularly and stick to damp material
The melting temperature of the plastic is low
At the mouth and the channel has sharp edges
Removes moisture and adjusts the right proportion of material Polishing the spray mouth and channel
Increase the plastic flow temperature to create bonding 5.Color change
The feeding chamber is too long to fulfill the mold at high temperatures
Color of milling material difference with recycled material
Keep the material clean before pressing
Reduce friction of the conductor system to avoid overheating Avoid the accumulation of gas that burns the product
Choose the right screwdriver Reduced feed drill temp and nozzle temperature
6 Flash The molds doesn’t tight together
Is not sufficient to withstand the molding pressure
Ensure the closure between the two halves of the mold
Increase the bearing capacity of the molds by supporting panels Increase clamping force of the machine
Excessive local coagulation increases the pressure inside the mold
Heat is too high and pressure too high
To prevent overheating, it is essential to lower the temperature of the feeding compartment and nozzle Additionally, reducing spray pressure while increasing pressure time and decreasing spray velocity can help mitigate back pressure issues.
7 Warp Cooling between regions is unequal, causing the product is shrinkage in different directions This is the main cause of the warping
The work piece are warped due to two-sided cooling is not the same…
Design cooling system for evenness
Reduce the thickness into work piece if possible, or add to the claw, stiffener
Set the mouth to allow the flow to flow in one direction
8 Short shot The plastic line is restricted because the conduit is frozen
The mold is so complex that the flow is blocked
Get out of the mold is not good
Plastic flow or mold temperature is too low
Pressing Capacity (cm3/s) or ram speed is too low
Mold leakage and volume of material also cause lack of material
Can increase the product thickness to expand the flow Place the gate at a place of great thickness
Increase the size of the gate, size of runner or quantity of nozzle to reduce line resistance
Place the ventilation openings in places where it is difficult to fulfill or increase the number of exhaust holes
Increase in pressure (about 70 - 80% of maximum pressure) Increase the spraying velocity so that the filler fills the cavity more quickly
9 Weld line The position of the gate is deviated
Place the gate of the spray to balance the flow
Table 2.11: Some failure on injection molding products
1 Hexagonal screw: Fixed the parts with each other
2 Location ring: Make sure the sprue bushing and nozzle are concentric
3 Sprue bushing: Put the plastic into the mold, usually it is on the top clamp plate
4 Cavity plate: Contains the cavity or cavity insert to shape the products, which is installed into the top clamp plate
5 Guide Bushing: Guide the guiding shaft to restrict the wear of the mold
6 Top clamp plate: Clamp the fixed part of the mold with the fixed plate of the plastic injection machine
7 Ejection pin: Push the product out of the mold
8 Return pin: associated with the spring, put the retaining plates and ejector plate return to the old position
9 Core plate: Contains the core or core insert to shaped the products, which is install into spacer block or support plate
10 Guide pin: guide the cavity plate and the core plate
11 Support plate: keep the mold from being bent
12 Support pillar: create space for product
13 Ejection retaining plate: holding plates and bales
14 Ejection plate: Combined with push plate and push button to push the part out of the mold
15 Bottom clamp plate: clamp the movable part of the mold with the movable plate of the plastic injection molding machine
16 Springs: to ensure the plates and plates push back to the old position after the flattening
17 Return pin: together with the spring put the retaining plates and plates back to the old position after the flattening
2.6 Some common types of molds
2.6.1 Two plate mold with cold runner
Two plate mold are the most common molds With three plate molds, the molds are simpler, cheaper and have shorter injection cycles
For two plate mold has one cavity not need runner, which the plastic will fill directly into the mold through sprue bushing
When designing a two-plate mold with multiple cavities, it is crucial to focus on the runner and nozzle configuration to ensure simultaneous filling of the mold with plastic.
Figure 2.4: Two plate mold using cold runner
2.6.2 Two plate mold with hot runner
The hot runner system keeps the plastic in a liquid state through consistent heating, eliminating the need for a plastic channel in the extrusion process and minimizing excess plastic waste.
No stain on the product
Control filling and flow of plastic
Price is higher than the two plate mold with cold runner
Difficult change color of material
Temperature control systems are easy to failure
Not suitable for low heat-resistant materials
Figure 2.5: Two plate mold with hot runner
In a three-plate mold, the channel system is positioned on the second plate, running parallel to the main molding face, in contrast to the two-plate mold design.
14 second plate, runner and sprue bushing can be removed from the product when opened Mold (self-cut glue tail)
Three plate mold is used where the entire channel system can’t be located on the same surface as the two plates mold This could be due to:
To achieve optimal plastic flow in a mold with multiple cavities, it's essential to utilize more than one injection point Proper design of the runner system, ideally positioned away from the die face, ensures balanced distribution of plastic, enhancing the efficiency of the injection molding process.
The feature of the three plate mold is the self-cutting of the glue tail
To enhance productivity and reduce costs in high-volume production, it is essential to optimize molding processes However, this focus on efficiency can complicate design, processing, and assembly due to challenges related to flatness and concentricity.
The pushing system must be specially designed because the two motions push against each other
Must use some mechanical details to create the mold movement
When designing a mold, certain product features may prevent removal in the mold opening direction, necessitating the use of lateral cores Various methods can be employed to create lateral surfaces, including camshafts, cam faces, latches, double latches, dog feet, and cone latches.
Figure 2.8: Remove the side face
Figure 2.9: Remove the side-by-side with a hydraulic cylinder
The lace element consists of inner and outer lace There are many lacing looms such as: forced latch release, latch release with latching, threaded engagement, gear release, latch release
Figure 2.10: Remove the threaded latch
2.6.7 Comparison between advantage and disadvantage of some kind of molds
Comparisons Two plate mold Three plate mold
- The ejection periodical is short
- Reduce the number of machines for ejector process
- The cost is lower than the mold have hot runner
- Less failure than the mold have hot runner
- May be suitable for low heat- resistant materials
- Suitable for automation, series production
- The number of products is much more 3 to 4 times than normal molds
- Reduce the number of workers
- Allows production from small parts to big parts
- No trace of the gate on the products
- Can be controlling the fulfill and the flow of the plastic
- Increase the quality of the product
- Only use for parts that require a low accuracy
- The process of full automation in working process is low
- Can't use for machining products that require high complexity
- More complex and expensive than two plate mold
- The injection cycle increases due to the flow of the plastic to fulfill molds is too long
- Need the high pressure to fulfill
- Manifold system must be continuously heated
- The change of the heat distributor and nozzle make a failure because of the thermal expansion
- Price is higher than two plate molds have cooling system
- Temperature control system easily damaged
- Not suitable for low heat-
18 complex and meticulous resistant materials
- Easily damaged, installation and maintenance costs are high
- For short-life products such as civil electronics (in a few months)
- Use for products requiring less gate
- Applications for household appliances, personal belongings
- High quality products such as phone case, computer case or electronic components…
- Products has thin and complex shapes
- Industrial products (high quantity) -The product is thin, short bottom
Table 2.12: Comparison between advantage and disadvantage of some kind of molds
For the reasons to select kind of mold:
After comparing, we choose to make spoon molding by two plate because of some reason
Spoons are a widely used and affordable kitchen utensil Manufacturing them using three-plate molds or stack molds can be a cost-effective solution for production.
Reasonable because the expense of three plate mold and stick mold is expensive
Two plate mold to produce easy and still has a beauty and quality like other mold
Structure is kind of simple and helps the worker can assembled and fix easy when it has problem
The tolerance of product is not too high So we can do it with the two plate mold.
Structural plastic molds
1 Hexagonal screw: Fixed the parts with each other
2 Location ring: Make sure the sprue bushing and nozzle are concentric
3 Sprue bushing: Put the plastic into the mold, usually it is on the top clamp plate
4 Cavity plate: Contains the cavity or cavity insert to shape the products, which is installed into the top clamp plate
5 Guide Bushing: Guide the guiding shaft to restrict the wear of the mold
6 Top clamp plate: Clamp the fixed part of the mold with the fixed plate of the plastic injection machine
7 Ejection pin: Push the product out of the mold
8 Return pin: associated with the spring, put the retaining plates and ejector plate return to the old position
9 Core plate: Contains the core or core insert to shaped the products, which is install into spacer block or support plate
10 Guide pin: guide the cavity plate and the core plate
11 Support plate: keep the mold from being bent
12 Support pillar: create space for product
13 Ejection retaining plate: holding plates and bales
14 Ejection plate: Combined with push plate and push button to push the part out of the mold
15 Bottom clamp plate: clamp the movable part of the mold with the movable plate of the plastic injection molding machine
16 Springs: to ensure the plates and plates push back to the old position after the flattening
17 Return pin: together with the spring put the retaining plates and plates back to the old position after the flattening.
Some common types of molds
2.6.1 Two plate mold with cold runner
Two plate mold are the most common molds With three plate molds, the molds are simpler, cheaper and have shorter injection cycles
For two plate mold has one cavity not need runner, which the plastic will fill directly into the mold through sprue bushing
When designing a two-plate mold with multiple cavities, it's crucial to focus on the runner and nozzle configuration to ensure that the plastic fills all molds simultaneously.
Figure 2.4: Two plate mold using cold runner
2.6.2 Two plate mold with hot runner
The hot runner system keeps plastic in a liquid state during the molding process, eliminating the need for a plastic channel and significantly reducing excess material.
No stain on the product
Control filling and flow of plastic
Price is higher than the two plate mold with cold runner
Difficult change color of material
Temperature control systems are easy to failure
Not suitable for low heat-resistant materials
Figure 2.5: Two plate mold with hot runner
In a three-plate mold, the channel system is positioned on the second plate, running parallel to the main molding face, which distinguishes it from the two-plate mold design.
14 second plate, runner and sprue bushing can be removed from the product when opened Mold (self-cut glue tail)
Three plate mold is used where the entire channel system can’t be located on the same surface as the two plates mold This could be due to:
To effectively utilize a mold with a cavity requiring multiple plastic injection positions, it is essential to balance the flow of plastic to the runner This necessitates designing a runner that is not positioned directly on the die face.
The feature of the three plate mold is the self-cutting of the glue tail
To achieve high-volume production while boosting productivity and minimizing costs, it's essential to consider the impact on design, processing, and assembly Challenges may arise in maintaining flatness and concentricity, which can complicate the overall manufacturing process.
The pushing system must be specially designed because the two motions push against each other
Must use some mechanical details to create the mold movement
When designing a mold, certain product features may prevent removal in the mold opening direction, necessitating the use of lateral cores Various design options for the lateral surface include camshafts, cam faces, latches, double latches, dog's feet, and cone latches.
Figure 2.8: Remove the side face
Figure 2.9: Remove the side-by-side with a hydraulic cylinder
The lace element consists of inner and outer lace There are many lacing looms such as: forced latch release, latch release with latching, threaded engagement, gear release, latch release
Figure 2.10: Remove the threaded latch
2.6.7 Comparison between advantage and disadvantage of some kind of molds
Comparisons Two plate mold Three plate mold
- The ejection periodical is short
- Reduce the number of machines for ejector process
- The cost is lower than the mold have hot runner
- Less failure than the mold have hot runner
- May be suitable for low heat- resistant materials
- Suitable for automation, series production
- The number of products is much more 3 to 4 times than normal molds
- Reduce the number of workers
- Allows production from small parts to big parts
- No trace of the gate on the products
- Can be controlling the fulfill and the flow of the plastic
- Increase the quality of the product
- Only use for parts that require a low accuracy
- The process of full automation in working process is low
- Can't use for machining products that require high complexity
- More complex and expensive than two plate mold
- The injection cycle increases due to the flow of the plastic to fulfill molds is too long
- Need the high pressure to fulfill
- Manifold system must be continuously heated
- The change of the heat distributor and nozzle make a failure because of the thermal expansion
- Price is higher than two plate molds have cooling system
- Temperature control system easily damaged
- Not suitable for low heat-
18 complex and meticulous resistant materials
- Easily damaged, installation and maintenance costs are high
- For short-life products such as civil electronics (in a few months)
- Use for products requiring less gate
- Applications for household appliances, personal belongings
- High quality products such as phone case, computer case or electronic components…
- Products has thin and complex shapes
- Industrial products (high quantity) -The product is thin, short bottom
Table 2.12: Comparison between advantage and disadvantage of some kind of molds
For the reasons to select kind of mold:
After comparing, we choose to make spoon molding by two plate because of some reason
Spoons are a widely used and affordable kitchen utensil, making them a popular choice for manufacturers Utilizing a three-plate mold or stack mold for production can enhance efficiency and reduce costs in spoon manufacturing.
Reasonable because the expense of three plate mold and stick mold is expensive
Two plate mold to produce easy and still has a beauty and quality like other mold
Structure is kind of simple and helps the worker can assembled and fix easy when it has problem
The tolerance of product is not too high So we can do it with the two plate mold
SURVEY OF THE PLASTIC MOLDES ON THE MARKET
Take the survey about some types of plastic spoon on the market
As science and technology advance globally and nationally, the demand for a higher quality of life has surged In response, companies and factories are continually enhancing product quality to meet societal needs Among everyday essentials, the plastic spoon has become increasingly popular, serving various purposes in daily life across the domestic market.
Some spoon products are widely used in life
Figure 3.1: Some types of plastic spoon products on the market
While there is a wide range of plastic spoons available for take-away foods, most are designed for single-use, limiting their quality and durability Few options on the market offer high durability and are suitable for long-term use.
So my team is excited about the subject, and is inspired to design The plastic spoon samples are higher quality and more eye-catching
Discover the allure of luxury with our elegantly designed metal spoons, featuring unique handles and intricate shapes that surpass ordinary scoops Each spoon showcases a sophisticated pattern, celebrating beauty and opulence Our team has meticulously crafted a variety of models, selecting only the finest samples to elevate your dining experience.
Here are some models the team has designed for selection:
Print 3D to compare with the facts
After design go to printed 3D to compare with the facts About the dimension and the advantage when using this for the purpose of daily life
Figure 3.3: Some spoon samples printed 3D.
Technical requirements and aesthetic
The spoon is carefully rounded to avoid sharp edges, which can be used to eat rice or to cook the kitchen for the user's purpose
Technical requirements: Relative size, easy to use, not too thick as it will waste materials.
Cosmetic requirements: eye-pleasing, unbroken bends, no traces on the product when designing the push system
After printing 3D, there are 6 spoon, we have choose:
For the reasons to select that sample:
Many products on the market are designed for short-term use and often feature a thin construction This highlights the need for durable, high-quality spoons that are thicker and built to last.
About the shapes, with the idea follow up with the spoon by porcelain material and pasting some imaging curve line abide by traditional of Viet Nam
There are some spoons has a shape quite outstanding and different with some plastic spoon in the market, so it might make the user feel impressive
PTC SOFTWARE PTC CREATIVE PARAMETRIC 3.0 –
PTC Creo parametric software 3.0
Figure 4.1: Software and interface work
PTC Creo Parametric 3.0, developed by Parametric Technology Corp (PTC), is an advanced software solution released in Vietnam on August 8, 2014, as an upgrade from PTC Creo Parametric 2.0 This latest version, previously known as Pro/Engineer, enables users to directly open, read, and edit 3D data from various sources such as Catia and SolidWorks without the need for conversion to intermediate file formats like IGES or STEP.
PTC Creo Parametric 3.0 software offers comprehensive solutions for design concepts, detailed mechanical product design, mold creation, and CNC machining, including advanced 3-5 axis capabilities This software enhances Italian design by prioritizing optimized design and faster production, ultimately boosting user performance.
This application utilizes assistive technology to enhance product development by allowing users to share design ideas and various 3D details within a single CAD drawing Users have the flexibility to select multiple products, enabling them to refine and improve their design concepts effectively.
PTC Creo Parametric 3.0 is an all-in-one CAD/CAM/CAE solution ideal for mechanical engineering design and the molding industry It facilitates a seamless production process by using consistent materials across design, mold making, mold extraction, and three-axis CNC machining programming This integration ensures that data is shared and continuously updated, creating a closed-loop system that allows companies to effectively control every stage of production.
PTC Creo Parametric 3.0 stands out for its seamless data import and export capabilities, enabling users to open, read, and edit files effortlessly This software automatically updates with various 3D CAD applications, making it user-friendly for manipulation and training, thus enhancing the learning experience for users.
24 save time work, no additional cost to buy the copyright of different vendors, but still ensure the source material…
The Multi Cad feature in Creo 3.0 enhances workflow by allowing users to open files directly from various software without needing to convert them to an intermediate format This functionality not only simplifies file access but also enables direct integration of files into assemblies Additionally, Creo 3.0 streamlines the updating of templates, as new templates can be easily added to reflect changes across other objects This is particularly beneficial for companies managing complex product designs, where multiple freelancers may use different software With Creo 3.0, managers can effortlessly consolidate files from various sources and update templates in just a few steps, making it a standout feature of this version.
Some features of the software:
PTC Creo Parametric 3.0 offers a versatile product design experience, enabling users to create products using simple tools like Extrude and Revolve, as well as advanced commands such as Blend and Warp The software supports parametric design, allowing for rapid modeling of standard machine parts Additionally, PTC Creo Parametric 3.0 facilitates step-by-step modifications of design parameters, automatically updating subsequent steps for enhanced efficiency.
PTC Creo Parametric 3.0 effectively simulates the molding processes for product design, enabling users to calculate material shrinkage and automatically create mold shapes based on specimen details Additionally, it features the Mold Cavity function, which allows for the simulation of mold release, enhancing the overall design efficiency.
Programmable machining with PTC Creo Parametric 3.0 software enhances CNC machining flexibility and ease of use, offering users a diverse range of machining options, including Profile, Pocketing, Face, Roughing, Finishing, and Engraving.
• Users can also use the outer surface, top face, lathe, groove, thread, etc on rotating surfaces with ease
Dynamic simulation in PTC Creo Parametric 3.0 enables users to assemble detailed components into a complete product and create functional couplings that facilitate movement within the model Additionally, this software offers advanced capabilities to test stress, displacement, and both linear and nonlinear deformation, allowing for the identification and prediction of potential material failure.
PTC Creo Parametric 3.0 includes a robust module for generating 2D drawings, allowing users to create vertical and horizontal projections from 3D models This software also offers a variety of symbols, including roughness and geometric tolerance indicators, which enhance the completeness and creativity of the drawings while reducing manual effort.
Figure 4.4: Drawing module of the software.
Process of mold design
As far as the safety of plastic food products is concerned, PP (polypropylene) is recommended as a spoon Because of the following reason:
• High mechanical strength (tear and tear strength), quite rigid, not flexible as PE, not stretched so long to be made into fibers
• Can use in the high temperature
• The cost of the plastic beads kind of cheap with another the same quality
• Transparent, high gloss surface for high printability, clarity
Figure 4.5: Basic information about plastic PP
Figure 4.6: Information about temperature in injection mold
Products are designed with a thickness of each product different
Figure 4.7: Checking the product thickness
Choose 2 samples with minimum thickness in the design process to test Through which to check the thickness as follows:
• Meaning of inspection and conclusion
Understanding product thickness is crucial for optimizing injection molding cycles, as it helps reduce cycle times and minimizes errors, leading to improved fill times This knowledge not only lowers production and mold costs but also conserves materials while enhancing product efficiency Proper thickness prevents defects like warping, holes, dents, and welds Additionally, it significantly influences the product's hardness, insulation, heat resistance, aesthetics, and overall cost.
Conclusion: The product is reasonably designed, the difference between maximum and minimum thickness is negligible This will save materials and avoid defects
4.2.3 Detach angle of the product
Based on the outward appearance of the product samples, the angle of escape can be seen to be quite favorable Only spoon has detach low angles should be calculated
Figure 4.8: The product needs to check detach angle
• Theoretical calculation of full angle extrusion
According to the following graph:
Figure 4.9: Graph advice of detach angle
With A is the width, B is the beveled corner, C is the depth
The dimensions indicate that A measures 6.97 mm and c measures 9.39 mm, highlighting a significantly large beveled corner This observation is further supported by the table, which shows that the angle is considerably larger compared to other measurements.
By the following formula: Tan B= 𝐴
It is easy to calculate the angle of discharge of the product
• Check the mold detach angle on the product
The product has a large detach angle if the preliminary view is predictable value is about 37˚38
Conclusion: Large escape angles allow the product to easily escape the mold without excessive thrust, while reducing the friction between the product surface and the mold surface
Plastic shrinkage (plastic shrinkage) or shrinkage is a top priority in plastic mold design That is the phenomenon of the physical volume of plastic varies from liquid to solid state
Determining the correct shrinkage factor will cause the product to shrink or other errors Types of shrinkage:
Shrinkage in the pressing cycle
Shrinkage after removal from the mold
The total shrinkage is equal to the sum of the two types of shrinkage
How to apply the shrinkage factor to the product
Depending on the stage of design calculation to determine the shrinkage
Example: An analysis of the compression stage followed by the cooling of the new period calculates the shrinkage factor
Table 4.1: Table of shrinkage of commonly used plastics
Steps of mold extraction process
B1) The working environment of the mold: New >> Manufacturing >> Mold cavity
B2) Get product into work environment
Figure 4.13: Take product into the work environment
B3) Create work piece and active
Figure 4.14: Create casts and active
Figure 4.15: Enter the shrinkage factor (PP)
B5) Create a mold by using a sweep command
Figure 4.16: Create a mold by using a sweep command
There are the one example to split spoon For every 6 spoons also do like that
4.2.7 Find the best gate location by Moldex 3D simulation
In today's manufacturing landscape, the integration of CAE (Computer Aided Engineering) with CAD/CAM-CNC technology is essential CAE is increasingly vital in the mold industry, facilitating simulation and analysis that help reduce costs, minimize damages, and optimize the plastic molding process.
Various CAE software, including Mold Flow and Moldex 3D, are utilized in mold analysis In this project, we will employ Moldex 3D RI4 software to effectively analyze and simulate the plastic injection process for our products.
First create a working environment in Moldex 3D designer and import the product into the work environment
To find the best gate location, in step 2:
Select Build runner tool select Gate Location Advisor
Figure 4.19: Step 2 Build Runner System
Figure 4.20: Best position for non-gating side direction Z
Figure 4.21: Best position for non-gating side direction X
Figure 4.22: Best position for non-gating side direction Y
Figure 4.23: Best position for non-gating side direction Z
Figure 4.24: Best position for non-gating side direction X
Figure 4.25: Best position for non-gating side direction Y
But some position is only appropriate with three plate mold so we have to consider gate location compatible with the two plate mold
We just select 2 spoon to simulated because the shape of spoon quite the same
This position compatible with two plate mold
Flow of plastic comply with the gravitation
It is beginning in the top of spoon can help gate contribute easy fulfill
Flow of plastic is divided balance It can reduce some failure of product
Disadvantage Location of the gate quite difficult to design and manufacture
This position appropriate with three plate mold
This position compatible with two plate mold
Flow of plastic comply with the gravitation
It is beginning in the top of spoon can help gate contribute easy fulfill
Flow of plastic is divided balance It can reduce some failure of product
Disadvantage Location of the gate quite difficult to design and manufacture
This position appropriate with three plate mold
Table 4.2: Comparisons for non-gating side direction
After comparing all factor on table 4.2, we decided to choice the side direction Y
Because it’s quite easy to design and manufacture
It is can design with the two plate mold
Design dimensions according to theory
As stated in the headers the largest thickness of is Smax=5 (mm)
So according to the formula above dF≥6 (mm) choose dF (mm) depend on the diameter of the nozzle can choose dS=3 (mm), choose α≥4 0
L: length depending on the mold structure of conditional: L≥(dF-dS)/2tanα
The nozzle of type SW-120B is diameter= 2mm so choice ds= 3mm is Ok
Figure 4.28: Some types of press nozzle
For optimal machining and spray placement, it is recommended to choose a side spray nozzle due to the product's simplicity and its multi-pleated structure, especially when filling is inadequate Additionally, the design should focus on the channel structure and limit the maximum length to minimize material wastage.
With the simple shape of the spoon detail select the gate commonly that injected into side of the spoon
Figure 4.29: Channel and gate selection
Figure 4.30: Recommended size for gate edges design
For details with the largest thickness: S = 5 mm, Select R= 6mm
For the reason to choice this kind of runner
It’s suitable with product has a high thickness and can help flow of plastic inject into the spoon easily
Easy to design and fix
4.2.9 Arrangement pisition of spoon on cavity
Solution 1: Arrange 6 spoon in a circle
Figure 4.32: Product and runner in a circle
Solution 2: Arrange 6 spoon in a row
Figure 4.36: Product and runner in a row
Advantage Spoon is divided in a circle so it’s help flow of plastic to fill in cavity easy and balance at the same time
Spoon is divided in 2 row, so we can reduce much material Because we can control the space between 2 spoon
The design of the Disadvantage Spoon features a circular shape with a diameter of at least 450mm, resulting in a significant gap between two spoons that cannot be minimized This design not only leads to inefficient use of space but also requires a considerable amount of raw material.
Spoon is divided in 2 row it’s make flow of plastic hard to fill in the cavity at the same time
After comparing between two solutions, we decided to select solution 2 because it’s reduce row-material It’s meaning reduce expense and cost of material
In addition to the challenges presented by solution 2, there is an issue with gate contribution, particularly evident in positions C and D as shown in figure 4.34 To effectively design the gate contribution, it is necessary to rotate the two middle spoons.
After all, we have a result of core and cavity
Figure 4.39: Cavity and core finally
4.2.10 Design runner and paste curve line on cavity plate and core plate
Pasting curve line by CAD 2007
Figure 4.40: Paste curve line on cavity plate
Figure 4.41: Paste curve line on core plate
4.2.11 CAE for flow analysis of plastics, welding fault and where is concentrating air trap
Create a new project in Moldex 3D RI4:
After creating the project, set up the test conditions with Create New Run 6 steps: OptionMeshMaterialProcessComputationCheck run
Parameters of injection moulding conditions:
After setting the parameters on the software, select Analysis to conduct analysis filling process So, we can see defect in welding and where is concentrating the blow hole
Figure 4.44: Conduct Filling analysis on Moldex 3D
Time to fulfill the product
According to simulation results, time to fulfill the product is 4s longer than the original calculation (3.89s)
With runners and gate contribution as designed, filling in the mould (100%) is guaranteed no gaps can’t be filled, using only one gate contribution for one mold
Injection pressure during fulfill process
The smallest injection pressure of the product is less than 27 (Mpa), 1 MPa 10.197 kg/cm², so the injection pressure about 297 (kg/cm 2 ) Compared with the data of the machine
6 Plasticizing Capacity (PS) 74 (kg/hour)
Table 4.4: Data of injection moulding
It is possible to confirm that the injection pressure is perfectly for the machine
Shrinkage of from 0.675 to 2 (%) is acceptable
Ability to fill at the same time
The Melt Front Animation analysis reveals that the plastic flow fills the product almost simultaneously, highlighting the effective design of the runner and gate system.
Check for where is concentrating an air trap and weld line
Conclusion: The products are injected fairly equal, injection pressure and temperature at the product are almost the same So, an errors sush as Weldline or Air trap are acceptable
Design of cooling line size based on thickness of the product
Products with w = 3.5 mm, according to theory chapter 14 have the following table:
Figure 4.52: Check the size and distance between the cooling lines
Because of the size have w= 3-5mm So, we can choose the design data as follows:
The diameter of the regular cooling channels d= 10mm,
However, to ensure the firmness of the mold we should choose the distance b= 50mm
Design Cooling systems on Moldex 3D software
Cooling system simulation on Moldex 3D software
The implementation steps are the same as filling system simulation the upper part
Figure 4.55: Conduct analysis Cooling system on Moldex 3D
The simulation results indicate that the cooling lines are utilized effectively, leading to efficient mold cooling and consistent heat dispersion These cooling lines play a crucial role in the overall cooling process.
Evaluate the effectiveness of the cooling system by comparing the Temperature and Average Temperature before and after its implementation The Mold, Sprue system, and Runner are maintained at a safe temperature to ensure optimal performance.
By vent on parting surface
Figure 4.59: Vent on parting surface
Vent guide: Must be designed to prevent material entering the vents during filling
Vent exit: Usually these are the areas far from gate, because when filled up, the air in the end zone is compressed
Number of vent exit needed
Figure 4.62: Number of vent exit needed
The total circumference of the relief slot must be approximately 30% of the perimeter of the part to ensure air escape
To increase an ability of air out of the mold, we should be arranged extra vent system of gases on runner
Vent system will be arranged into a closed loop around the perimeter of the runner and led out by the vent
Because the air has already existed in runner before the plastic is introduced
Therefore, when the plastic is introduced into runners, the air will be added to runners into mold cavity
The plastic with high temperatures and pressure available will continue increase in the mold cavity, causing overheating to damage parts
Therefore, design extra vent system of gases on runner to escape
Figure 4.63: The layout of vent system of gases through runner
Easy to work and clean
Can be placed anywhere on the Parting plane (MPK)
Vent should be designed so that air escape easily but the plastic doesn't flow out of the mold cavity
Depends on speed and flow when allocate Escape system of gases
Vent system of gases should't be allocated on too thin parts, ribs, abd blind holes
Figure 4.64: Air vent (Air escape) through push system on mold
Relying on the push system in the mold On these ejector pin, design torsion groove to the air escapes under these groove
Figure 4.65: The layout of the air vent on the ejector pin
Ejector pins are designed to operate effectively based on the clearance between the shaft and the hole during assembly The push system slides along the shaft to eject the part outward, necessitating an assembly with an aperture This aperture allows for air to escape, effectively eliminating any air traps that could hinder the ejection process.
- Path air into a gutter that surrounds the perimeter of the cavity mold
- The outside has a rubber sealing ring to isolate the outside and inside of the mold, prevent the outside air entering of the mold
- At the gutter: design the vents to connect to the vacuum pump
Figure 4.67: Vacuum system in mold
When the mold is sealed, the vacuum pump is activated to remove all air, creating a complete vacuum inside the mold This ensures that the injection of plastic is not hindered by any residual gas, allowing for a smooth and efficient molding process.
Figure 4.68: Cooling system insert, slide
For ribbed details, utilizing a path on the die or ejector pin is impractical; instead, employing insert inserts is a viable alternative This method effectively utilizes the gap between the two components to create an escape gutter.
Actually there are many exhaust options that can be used, depending on the shape of the molding, injection port position, machining capability, spray pressure
With the simulated air trap, the air trap of the spoon is concentrated only at the final filling, and other areas are almost hardly appears
So choose the type of exhaust air on the mold because it is a simple type of effect well besides it is easy to work and clean
With the type of air trap on the molded section as shown above: consists of two main parts are the vent and the air path
The depth of the air path is typically shallow to minimize material leakage, and this depth varies based on the viscosity of different plastic types.
Given in the following table:
Table 4.5: Table of depths of vent land of some materials
The product uses PP plastic so the air path is within the between: 0.0127-0.03048mm
Choosen depth vent guide a= 0.015mm
Length vent guide in between : 0.508-0.762mm
Choosen length vent guide b= 0.6mm
Width of vent unlimited, but in fact in between : 3.175÷12.7 mm
Vent exit: Bring the air out of the mold Has bigger depth and width than vent land, to reduce the pressure and the air out completely
Dimension as : 20.d (d: the depth vent guide)
The depth vent exit a= 20.0.015= 0.3mm
Width of vent exit is equal to width vent guide
The length of vent exit from the vent guide leading out of the mold
It is essential to position air vents at various locations along the runner system, particularly in the last filled areas, which are often situated far from the plastic entrance This is crucial because, as the plastic fills, the air becomes compressed and can become trapped, making these locations particularly prone to air entrapment.
Regarding the number of relief slot:
SOFTWARE
Overview of Moldbase Extension (EMX)
Expert Moldbase Extension (EMX): The module is directly run on PTC Creo Parametric 3.0 software to support the mold design quickly, accurately and efficiently
5.1.2 Design the mold with EMX
Step 1: Create working environment working environment:
Figure 5.1: Creating a working environment in EMX General
Step 2: Choose the size of the standard mold cover
Figure 5.2: Choose the size of the standard mold cover
Based on the size of the design, choose the right molding With the cavity mold on the mold select the size 250-400 (mm)
Step 3: Adjust the size of the molding frame to suit the design
Figure 5.3: Adjust the size of the mold plate
Step 4: Make the molds in the mold housing
Figure 5.4: Inserting the mold into the mold housing
Step 5: Insert the basic components into the mold
Select the Locating Ring MH item and select the appropriate type
Figure 5.5: Select type of locating ring
Sprue bushing: Choose Sprue Bushing and choose the right type
Figure 5.6: Dimension sprue bushing design
Choose Guide Bush and choose the right type
Figure 5.7 : Dimension guide bush design
Choose Leader Pin and choose the right type
Figure 5.8 : Dimenstion leader pin design
Sping: Choose Spring and choose the right type
Choose Ejector Pin and choose the right type
Figure 5.10 : Dimenstion ejector pin design
Figure 5.11: Complete mold assembly EMX Genaral
MACHINE MOLD AND ASSEMBLIES
Select the method and direction of machining
To make the process simple and cost effective Select the combination method has been machined on CNC machine and machine
Back plates, ejector retainers, and support plates are straightforward assemblies Programmers first mark these components on the CNC machine, after which they are transferred to a semi-automatic machine for operations like drilling holes and creating threaded connections.
Two core molds and a choice of machining method on CNC machines.
Diagnostic steps before machining
Clean the face of the steel and eto
Check dimenstion steel, check the drawing
Use a watch over check plane
Fix the knives on the knife table
Standard set up of steel
Machining the plate molds
Choose material make mold: Steel C50
6.3.1 The plate molds are machined on CNC machines and on the machine
- Hole position tolerance: Need for exactly and concentric high with the hole of the molding cavity
- Tolerance of diameter size: Not high due to not participating in assembly But make sure larger than the bolt, to easily remove the bolt b) Hold assemble sprue bushing
- Hole positional tolerance: high hold the concetric sprue bushing
When assembling the sprue ring, it is crucial to maintain proper dimensional tolerance to ensure a secure fit that is neither too tight nor too loose This assembly process should allow for residual space, ensuring the sprue ring is firmly inserted while avoiding any excessive pressure that could damage the ring.
The top and bottom surfaces require a high-gloss finish, ensuring that both sides are parallel to each other Additionally, the alignment between the underside and the top of the female component must be precise This assembly is designed to be permanent.
- Machine methol: rough milling + finishing
For 4 sides don’t affect to assembly , So the gloss and the parallelism are not high
Table 6.1: Processing technology for top clamp plate
Cutting Tools Cutting mode Note
Figure 6.2 : Top clamp plate after manufacture
77 a) Hold bolt : Similarly the bolt holes are clamp plate b) Hold piston push of the press through: Tolerance not obligate too high
Machine methol: rough milling c) Request for bottom clamp plate: Similarly top clamp plate
Table 6.2: Processing technology for bottom clamp plate
Figure 6.4 : Bottom clamp plate after manufacture
Figure 6.5 : Spacer block a ) Bolt hole
- Hole position tolerance: Need for exactly and concentric high with the hole of the molding core and clamp plate.225
- Tolerance of diameter size: Not high due to not participating in assembly But make sure larger than the bolt, to easily remove the bolt
Machine methol: rough milling b) Request for spacer block
For 2 sides of the core plate and the clamp plate requires high parallelism, and relative gloss The assembly time is not open
Machine methol: rough milling + fishing milling
Table 6.3: Processing technology for bottom clamp plate
Cutting Tools Cutting mode Note
Figure 6.6 : Spacer block after manufacture
Purpose: assembly and hold return pin
- Position tolerance: Need for exactly and concentric high with the hole return pin on core mold
- Tolerance of diameter size: Not high
Machine methol: rough milling b) Hold lace assembly bolt
Purpose: assembly bolt for hold retainer plate and ejector plate with together Request
- High position tolerances are required when assembly retainer plate and ejector plate correctly, without deviation Screw in easily
- Tolerance of diameters according to standard threaded panel
Machine methol: rough milling + fishing milling + taro c) Hold assembly ejector pin
Purpose: assembly and retain ejector pin
- Hole position tolerance: concentric high with the hole of ejector pin on the molding core
- Tolerance of diameter size: Not high
- Machine methol: drill d) Request for return plate
- Request for high parallelism and relative gloss of face contact with ejector plate
- Machine methol: rough milling + fishing milling
- For the sides rest of the requirements are relatively low
Cutting Tools Cutting mode Note
Table 6.4: Processing technology for Ejector retainer
Figure 6.8 : Ejector retainer after manufacture
- Position tolerance: Need for exactly, concentric with the hole lace return plate
- Tolerance of diameter size: Not high due to not participating in assembly But make sure larger than the bolt, to easily remove the bolt
- Machine methol: drill b) Request for retainer plate
Request for high parallelism and relative gloss of face contact with ejector plate Machine methol: rough milling + fishing milling
For the sides rest of the requirements are relatively low
Cutting Tools Cutting mode Note
Table 6.5: Processing technology for ejector plate
Figure 6.10 : Ejector plate after manufacture
6.3.2 Machining the Core plate and the Cavity plate
Prepare 2 workpiece of the following sizes:
Prepare retainer: Eto, CNC machine
Table 6.6: Processing technology for the cavity plate
1 Head face milling CNC Milling machine
2 Rough milling Máy phay CNC
CNC Milling machine Work offset
CNC Milling machine Work offset
Table 6.7: Sheet technology for cavity plate
F (mm/sec) t (mm) a (mm) Note
Figure 6.11 : Cavity plate after manufacture
1 Head face milling CNC milling machine One-sided milling
CNC milling machine Work offset
3 Finishing milling CNC milling machine Work offset
Table 6.8:Processing technology for the Core plate
F (mm/sec) t (mm) a (mm) Note
Table 6.9 : Sheet technology for core plate
Figure 6.12 : Core plate after manufacture
Mold assembly
Step 1: Assembly Guide bush into the cavity plate
Step 2: Assembly the Cavity plate with the top plate
Step 3:Assembly the Sprue bushing into the Clamp plate and assembly 6 bolt to keep top clamp plate and cavity plate
Step 4: Assembly the Locating ring with the top clamp plate and 3 bolt keep the locating ring The fixed mold has been completed
Step 5: Assembly the guide pin into the core plate
Step 6: Assembly the 3 ejector pin into the ejector retainer plate at the same time when installing the 4 return pin
Step 8: Assembly ejector plate and ejector retainer plate
Step 9: Assembly 2 spacer block with bottom clamp plate
Step 10: Assembly bottom clamp plate with ejector plate and 2 pillar support
Step 11: Assembly bottom clamp plate with core plate
To here, we had completed part of moving mold
Assembly 2 part, we had a mold completely
Figure 6.23: Step 12 complete of mold