plastic injection molding sink mark

 

The reasons for sink mark in plastic products are as follows:

Reasons for injection molding sink mark

Sink marks in injection molding are common defects that occur when the surface of a molded part shrinks and creates a depression or dimple. This typically happens because the inner part of the material cools and shrinks faster than the outer surface, pulling the surface inward. Sink marks are most noticeable on thicker sections of the part or near ribs, bosses, or other features that create variations in wall thickness.

Causes of Sink Marks:

1. Insufficient Cooling Time:

• If the cooling time is too short, the outer surface solidifies while the inner material is still cooling and shrinking, causing sink marks.

1. Inadequate Holding Pressure or Time:

• Holding pressure helps pack additional material into the mold to compensate for shrinkage. If the pressure or time is insufficient, the material shrinks excessively, leading to sink marks.

1. Excessive Wall Thickness:

• Thicker sections cool more slowly, increasing the likelihood of shrinkage and sink marks.

1. High Material Shrinkage Rate:

• Some materials, such as semi-crystalline plastics (e.g., polypropylene or nylon), have higher shrinkage rates, making them more prone to sink marks.

1. Improper Gate Location or Size:

• If the gate is too small or poorly located, it can restrict the flow of material, preventing adequate packing and leading to sink marks.

1. High Melt Temperature:

• Excessive melt temperature can increase material shrinkage as it cools, contributing to sink marks.

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How to Prevent Sink Marks:

1. Optimize Wall Thickness:

• Design parts with uniform wall thickness to ensure even cooling. If thick sections are unavoidable, use coring or ribbing to reduce material volume.

1. Increase Holding Pressure and Time:

• Apply sufficient holding pressure and extend the holding time to pack more material into the mold and compensate for shrinkage.

1. Adjust Cooling Time:

• Ensure adequate cooling time to allow the entire part to solidify uniformly.

1. Use Low-Shrinkage Materials:

• Select materials with lower shrinkage rates, such as amorphous plastics (e.g., ABS, PC) or filled resins.

1. Optimize Gate Design:

• Use larger gates or position them near thicker sections to ensure proper material flow and packing.

1. Control Melt Temperature:

• Avoid excessively high melt temperatures to minimize shrinkage.

1. Add Mold Features:

• Incorporate mold features like gas vents or cooling channels to improve cooling efficiency and reduce shrinkage.

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Corrective Actions for Existing Sink Marks:

• Increase holding pressure and time.
• Reduce melt temperature.
• Extend cooling time.
• Modify part design to reduce wall thickness or add coring.
• Adjust gate size or location.

By addressing these factors, you can minimize or eliminate sink marks and improve the quality of injection-molded parts.

Plastic Thermoforming company in China

 

Vacuum Thermoforming in China

Vacuum thermoforming is commonly used for various plastic packaging china but has many applications from plastic

toys to aircraft windscreens to cafeteria trays.

Thin gauge (less than 0.060 inches) sheets are mostly used for rigid or disposable packaging. While thick gauge (greater than 0.120 inches) sheets are typically used for cosmetic permanent surfaces on automobiles.

Shower enclosures, and electronic equipment. A variety of thermoplastic materials can be used in this process, including the following:

Acrylic (PMMA)

Cellulose Acetate

Polystyrene (PS)

Low-Density Polyethylene (LDPE)

High-Density Polyethylene (HDPE)

Polypropylene (PP)

Acrylonitrile Butadiene Styrene (ABS)

Polyvinyl Chloride (PVC)

 

 

	Typical	Feasible
Shapes:	Thin-walled: Cylindrical The Thin-walled: Cubic Thin-walled: Complex
Part size:	Area: 0.04 in² - 300 ft²
Materials:	Thermoplastics
Surface finish - Ra:	60 - 120 μin	16 - 120 μin
Tolerance:	± 0.04 in.	± 0.008 in.
Maxwall thickness:	0.015 - 0.15 in.	0.002 - 0.25 in.
Quantity:	10 - 1000	1 - 100000
Lead time:	Days	Days
Advantages:	Can produce very large parts High production rate Low cost
Disadvantages:	Limited shape complexity Limited to thin-walled parts Scrap cannot be recycled Trimming is required
Applications:	Packaging, open containers, panels, cups, signs

 

Thick-Gauge Thermoforming in China

Thick-gauge--or "heavy-gauge"--thermoforming, manufacture parts with a thickness in the range of .060 to .310. This thickness creates sturdy, rigid enclosures. Perfect for enclosing things like electronic equipment in supercomputers. Materials used in thick-gauge thermoforming include flame-retardant ABS, polycarbonate, and a PC-ABS blend. Low volume orders are common, and a quality thick-gauge thermoforming company can do economical low-volume runs.

In addition, thick-gauge thermoformed must consider aesthetics. How the enclosure looks--since the enclosure is not going to be discarded like the packaging but is actually part of the product itself. For customers concerned with branding, the look of these enclosures. From color to logo placement.Is an important part of the thermoforming process. what to find a good thermoforming company that can meet your volume requirements and deadlines is critical in China. At CN-MOULDING, our award-winning thermoforming process takes your 3D injection files to finished parts in just 2-4 weeks.

Thick Gauge Thermoforming has cost an effective way

Whether for new products or updating existing products. Thick Gauge Thermoforming is cost an effective way to achieve the function, style. And durability is required for many applications. Chinese thermoforming companies have experience producing parts for a wide range of industries such as Communications, Search and Rescue, Construction, Automotive. And various military applications. Plastic thermoformed parts can be both lighter weight and offer greater impact resistance than comparable parts in metal. The Thick Gauge Thermoforming process allows for the material to be formed into more complex. And smoother shapes than traditional metal forming techniques can produce.

Plastic thermoformed parts also offer a nice appearance without additional surface finishing. Though color matched painting is an option. The benefit of plastic coloring is that it goes all the way through the material. So if the part is scratched it won’t show a different color below the surface. Special properties can be incorporated into materials. Such as UV protection, flame retardance, electrical conductivity, solvent resistance, food-grade, etc.

Reference for plastic packaging by CN Moulding.

Precision injection molding characteristics

 

Precision injection molding characteristics

Precision injection molding characteristics

     The Precision injection molding is generally referred to as the precision of forming parts and surface quality is demanding high technology, some people think that precision injection is the size of plastic parts to achieve the accuracy of 0.01 ~ 0.001 mm injection molding process. In recent years, with the electronic, medical, communications, automotive, and other industries. With the rapid development of people’s plastic products, high precision, high-performance requirements. The traditional plastic molding process has been difficult to meet the current high standards. Is one of the most important plastics molding methods. Therefore, precision injection molding technology more and more people’s attention. Making precision injection molding technology continues to progress, new technology continues to emerge. Factors that affect precision injection molding require high dimensional accuracy, low warpage, excellent transfer characteristics, and excellent optical properties.

Therefore, it is on the injection molding machine, injection mold, molding process, raw material properties. And formulations have special requirements, affecting the many factors of precision injection molding. According to the current actual production point of view, the impact of precision injection molding factors are the following aspects:

1. Plastic shrinkage design of precision plastic products, plastic shrinkage should be considered.
2. The shape and size of the product The shape and size of the plastic parts have a great impact on the accuracy of the parts, the production practice shows that the more complex the shape of the product and the larger the size, the lower the accuracy
3. Mold structure The accuracy of plastic parts and mold cavity number and production volume are closely related. It is also shown that the accuracy of the single-cavity mold structure is higher than that of the multi-cavity mold, and the accuracy of small-mass production is higher than that of large quantities.

Plastic mold manufacturer

 

Plastic mold manufacturer

When you develop a new plastic model, you need to find plastic moulding china to make the mold.
Since the company size, location and history are different. They will quote you different prices.at the moment lots of trading companies pretend to be a plastic mold manufacturer to dealing with you. They will take at least a 30% profit from you and do nothing. Just think about it. If your competitor finds a true plastic mold manufacturer but you find the trading company to develop the same project. They will have a 30% price advantage compared to you. Do you think if you have any chance to win the market?

 

How to find a reliable plastic mold manufacturer?

I think it’s better to spend some time to get to know one or China injection molding several plastic mold manufacturer really well. Visiting them is the best idea once you get a good feeling about it (after discussions about mold engineering or making a small test mold). When you have a good relationship with a plastic mold manufacturer. And you will know how they think about the technologies and use the same language to discuss mold engineering, more effective. You can move on to your project very fast. That’s where the profit is along with the life of the project. Steel is steel and CNC machines are the same for every shop. In the end, it counts on the people who work with you and if someone does a value stream analysis of a project, the mold quality will be different.

 

Visit the plastic mold plant

 

Visit the plastic mold plant and check the facility available with them. Injection molding company asks about his existing customers and main marketing. Check the molds which are in construction in the shop, see the project management system. Look at the sample components they made in the past. All this will give you an idea of the capability and the quality levels of plastic mold manufacturer.
Then check which is your most concern like, lead time of mold building, the finish of the samples, dimensional criticality, quality of steel. After-sales service like modification of mold based on the change in design change during the mold life, the durability of the product.

 

Know injection mold cost

The cost of mould includes： material fee + design fee + processing fee and profit + VAT + trial fee + packaging transportation fee. According to material cost calculation, mold price =(6~10)* material cost.

Visible, the cost of the mold is mainly in the technology and processing costs above, the material ratio is smaller. The more complex the structure of the mold, the greater the difficulty of production, the higher the cost of course. In addition, the higher the precision of the mold requirements, the greater the difficulty of processing, the greater the effort spent. Of course, the cost of mold production will go.

The most important is: find many plastic mold manufacturers for price and quality checks. Choose the best and proper one as your business partner.

Plastic Parts Flash Solution: A Comprehensive Guide

 Plastic parts flash is a common problem in the injection molding process. It refers to the excess material that protrudes from the molded part due to the presence of gaps or misalignment between the mold halves. This flash not only affects the aesthetics of the finished product but also compromises its functionality. Fortunately, there are several solutions to this problem, and in this blog post, we will discuss them in detail.

Optimize the Mold Design

The first step in preventing plastic parts flash is to optimize the mold design. This includes ensuring that the mold halves are aligned correctly and that there are no gaps or misalignments. The use of high-quality materials and precision machining techniques can also help to reduce the occurrence of flash.

Adjust the Injection Molding Process

Another solution to plastic parts flash is to adjust the injection molding process. This includes optimizing the injection speed, pressure, and temperature to ensure that the plastic material flows smoothly and fills all the cavities in the mold. The use of injection molding simulation software can help to identify potential issues in the process and optimize it accordingly.

Use Mold Release Agents

Mold release agents can also be used to prevent plastic parts flash. These agents are applied to the mold surface before injection molding, and they help to reduce friction between the mold and the plastic material. This, in turn, reduces the occurrence of flash and improves the overall quality of the finished product.

Implement Post-Molding Operations

Post-molding operations such as trimming, sanding, and polishing can also be used to remove plastic parts flash. These operations are carried out after the injection molding process and involve removing the excess material using specialized tools and techniques. However, this solution is time-consuming and can increase the overall production cost.

Use Automated Deflashing Equipment

Automated deflashing equipment is another solution to plastic parts flash. This equipment uses specialized tools and techniques to remove the excess material from the molded parts automatically. This solution is faster and more efficient than manual trimming and can significantly reduce the overall production cost.

Reference

1, Should be paid attention to, for the mold and excessive clamping pressure also can produce flash, parting surface, between the clip into the foreign body damage both mold and produces the burrs.

2, Injection mold material often use S50C JJS (Japan standard domestic 50 # steel) using HRC30 hardening of the special steel in advance, it is difficult to produce burrs in parting surface

Conclusion

Plastic parts flash is a common problem in the injection molding process, but it can be prevented using various solutions such as optimizing the mold design, adjusting the injection molding process, using mold release agents, implementing post-molding operations, and using automated deflashing equipment. Each solution has its advantages and disadvantages, and the choice of solution will depend on the specific requirements of the product and the production process. By implementing these solutions, manufacturers can improve the quality of their products and increase their competitiveness in the market.

Good Supplier Good Assistant

 

Find a good supplier of injection molding? Yes, We are

          The United States and European companies can produce perfect products, high precision injection molded parts also. Why set to purchase goal finally in China. This is a very interesting question, the price is a major factor, but now Southeast Asia or Mexico is much cheaper, so the system of integrated suppliers is the key issue today. We will explore how the real system integration suppliers. How to choose an injection molding supplier, especially you are a beginner to buy mould and plastic injection molding part from china company, we can find the following:

           The principal advantage of injection molding is the ability to scale production en masse. Once the initial costs have been paid the price per unit during injection molded manufacturing is extremely low. The price also tends to drop drastically as more parts are produced.

          As the integrated system of Chinese injection suppliers is committed to high quality and punctual delivery, while maintaining acceptable market prices, any kind of injection molding factory out of the market, will eventually be eliminated by the market.

          Our German clients MERKLE who is a robotic end arm leader once talked about one of his bad memories with me, when he started the business with a Chinese injection molding company dealing, simply promise company must not ideal supplier, China will go a long way to instill the enterprise executive ability, can reliable OEM suppliers.

         The injection molding China suppliers, production of the full set of solutions. I know my team to do due diligence to ensure customer satisfaction every day. This is we as a business to make money (after all, this is any commercial purpose). But if customers are satisfied with our products, and services he/they will be back to do business with us and recommend to other companies.

Good Supplier Good Assistant – Precision injection molding characteristics

      Precision injection molding is generally referred to as the precision of forming parts and surface quality is demanding high technology. Some people think that precision injection is the size of plastic parts to achieve the accuracy of 0.01 ~ 0.001 mm injection molding process. In recent years, with the electronic, medical, communications, automotive, and other industries. The rapid development of people’s plastic products, high precision, high-performance requirements.

       The traditional plastic molding process has been difficult to meet the current high standards. Is one of the most important plastics molding methods. Therefore, precision injection molding technology more and more people’s attention. Making precision injection molding technology continues to progress, new technology continues to emerge. Factors that affect precision injection molding require high dimensional accuracy, low warpage, excellent transfer characteristics, and excellent optical properties.

Mold design

 

mold design

• Injection molds design
• hot runner system
• Solidworks software
• Medical mold project
• Product description: Custom injection molds design services.-Rapid prototypes molds, injection molding. Plastic thermoforming, low prices fast turn around in Shanghai, China

Why do you need a china injection molding company to help you do a design job?

Because we can provide our clients with professional solutions to the industrial/mold design of new products. Let us help ensure your product can be manufactured. In the past 10 years, a lot of clients need such a design service. The customer will take some samples from the exhibition or competitor side. We will copy and change the style, structure from the old sample. Or our clients only have an idea for a product and they need to turn their idea into a real 3d model. During the design process, we will change the parts easier for molds tools making in the future.

It is really enhancing the value of products by the most economical investment and turning the solutions into the "Design keys" in practice.
Injection-molded plastic parts can be designed to provide good looking products that consumers want to buy at no additional cost over boring products that have no sales appeal. To do this you need the right product concept. The right people, and the right tools. We have the capacity to treat Solidworks, Pro/engineering, UGII, Catia famous 3D software.

Our experience and expertise in 3D software

With our experience and expertise in 3D software, technologies can help you in 3D Plastic product design. Our technology-based services in product structure analysis. Injection mould design and making, injection molding to an extra edge to enhance our core plastic product design capabilities. We can assist you with plastic product designing from the conceptual stage. Or if widespread modifications are required to go into the process. Working closely with rotational molder we ensure a successful launch of your product.

Our Design team with high-caliber, teamwork spirit, and innovation capacities. Our service is not only a concept for the design. But also considers really mould making in the future which will realize a material leap from initial ideas to final products.

Contact us now and you give get extra service not only simple plastic product design!

Design tips:

Sink mark

A Sink Mark can be defined as depression. resembling a dimple or groove.
Caused by the excessive localized shrinking of the material after the part has cooled.

How to reduce sink mark, design thickness consistent

However, there are several aspects of tooling design available to the toolmaker that can influence the sink. Cooling-channel design, gate type. And gate size can have a wide variety of effects. For example, a small gate such as a tunnel gate freezes off much quicker than an edge gate. Premature gate freeze-off will reduce the available packing time in the cavity. Which can increase the likelihood of sink marks?

 

Prevent Warping

Warp in injection molded parts is caused by uneven stress. There are only 4 primary plastic processing variables in the injection molding process. – Cavity pressure, melt temperature, fill rate, and cooling rate.
The general rule changes design Reduce thick and thin transition. Also, use ribs design instead of a big thickness area.

A draft angle of injection molds design in China

Plastic parts design a draft angle to prevent the part from sticking on the mold and the ejector marks a small push caused by the molding process. In addition, you need to have done enough product surfaces with polish and draft angles. Do not forget the ribs should not exceed 60% of wall thickness.