2025年4月14日星期一

4 solutions for injection molding in China 2025

 

4 solutions for injection molding  China in 2025

1, Filling the defect

It always shows incomplete filling or edge collapse. It will decide on a product, waste material, labor, and time. There is much possible reason: Such as nozzle temperature is too low, not enough supply, flowability not good. The injection pressure is low. The gate is too small or not right position, the mold surface is injection mould companies not smooth enough. The nozzle is blocked, venting problem

2, Flash or burr

It always happens in the parting line. It will increase the difficulty of machining or shape, even defective. The possible reason such as nozzle temperature too high, injection too much material, flowability is very good. Injection pressure too high, clamping force too small

3, Sink mark

It always caused by material shrink after injection molding. The possible reason such as nozzle temperature too high, resin supply not enough, shrinkage is too big. Injection molding pressure too low, holding time too short, injection speed too slow, mold temperature to plastic molding company high, cooling time too short, the thickness of the product is uneven, gate too small

4, Welding line

It always happens in a product that has holes or another shape. The possible reason such as nozzle temperature too low, the material is not dry up enough, injection speed is too slow, gate too small, venting is not good. Injection pressure too low or other reason

4 solutions for injection molding:

As we can see the types and causes of injection molding defects, almost every kind of defect is formed by the combined effects of many factors. All these reasons are performance and molding machines, molding material character, mold design structure and material, filling control systems, and injection molding plastics different operating processes related. Although injection molding technology development in some areas is very quick, technology is relatively mature. But accompanied by increasing difficulty defect control, which requires us to reduce and Troubleshoot plastic injection molding defects with the help of advanced theory and advanced technology tools.

 

The Irreplaceable Advantages of China's Precision Injection Molding Industry Amid Global Tariff Changes

 The U.S. tariff hikes and rising global trade barriers have forced manufacturers to reconsider their supply chains. However, Chinese precision injection molding companies like CNMOULDING remain indispensable in global competition due to their complete supply chain, advanced technology, rapid response capability, and significant cost advantages.

1. Highly Efficient Integrated Supply Chain

China boasts the world's most comprehensive plastic processing ecosystem, covering everything from mold steel and precision CNC machining to injection molding and surface treatment. Companies like CNMOULDING leverage industrial clustering to deliver precision molds in just 3-4 weeks, compared to over 8 weeks for most Western manufacturers.

2. Technological Leadership in High-End Markets

China's injection molding industry has evolved from low-cost manufacturing to producing high-precision, complex plastic components. For example, CNMOULDING's expertise in microcellular foaming, multi-material molding, and optical-grade plastic molding serves high-value industries like automotive and medical devices, matching global leaders in technology.

3. U.S. Manufacturing Shortcomings: Long Lead Times & High Costs

  • Development cycle: U.S. mold production takes 2-3 months, while Chinese suppliers like CNMOULDING can complete it in under a month.
  • Production costs: China’s total costs (labor, energy, and supply chain) are just 30%-50% of U.S. costs.
  • Flexible production: Companies like CNMOULDING support rapid small-batch, multi-variant production to meet dynamic market demands.

4. Strategic Response: High-End Innovation + Global Expansion

  • Technology upgrade: Focus on medical-grade and automotive-grade precision molding for higher margins.
  • Overseas production: Establish factories in Mexico and Southeast Asia to bypass tariffs while maintaining China’s core supply chain advantages.

Conclusion

While global tariffs increase trade costs, China’s precision injection molding industry—with its unbeatable combination of technology, speed, and cost—remains the optimal choice for international brands. Leading firms like CNMOULDING are reinforcing their irreplaceable position through innovation and strategic global expansion.

The factors affect the percentage of regrind materials

 The factors affect the percentage of regrind materials

The factors affect the percentage of regrind materials

The factors affect the percentage of regrind materials
The factors affect the percentage of regrind materials

1, The purpose: In order to control and improve the quality of plastic parts, reduce the cost of plastic parts and injection molding plant regrind materials management, to meet customer technical requirements.

2, The scope: for the injection of all of the Company ABS, PA66, PA6, PP plastic parts, and workshop back to powder, processing, storage, labeling, and other management regulations.

3, Regrind material recovery and grade classification

1, Recyclable materials:

A.Defective products produced during injection molding (such as scratches, incomplete, burr) and other defective products.

B, injection molding process generated in the runner compound (nozzle material).

C, other (such as: engineering testing and other models can not be shipped demolition of plastic pieces or scrap pieces).

2, Regrind materials level:

A, The first regrind materials: the new material produced by the first injection of plastic.

B, The second regrind materials: after the second injection of plastic produced.

C, The third regrind materials: the second or more (including three) after injection of plastic and scrap.

The bulk density of the regrind is probably the single biggest factor affecting how much regrind one can use.

If you are using a recycled film scrap that hasn’t been densified then you pay a tremendous penalty in your rate. There are densifiers like a Munchy that will compact the film scrap to something close to a virgin pellet. In this case, then you can use quite a bit of scrap – 20 – 30%.

Another thing affecting your percentage of regrind is the use of grooved feed sections for extruders. They really are not designed for anything but pelletized material. It is best not to use more than 5% regrind if you have a grooved feed otherwise the grooves will clog and production rate will drop significantly and product quality will also suffer.

In blow molding, for instance, it is not uncommon for bottlers to use 35% regrind as the moels and tails comprise a considerable amount of material in relationship to the end product. That stuff is usually compressed and put back in the hopper.

Pre-hot runner systems had a lot of regrind as dense material sitting in the runners and gates was recycled. Those rates were quite high. I have seen that as high as 50%.

The other points are quite well such as contamination from streams and other things that need to be considered. In the end, I would say there is NO rule of thumb it greatly depends on so many factors.

There is no 1 rule of thumb. It will depend on several elements;

What type of Polymer and how they degrade (heat stability and moisture content)

whether filled and type of filler. Glass length will degrade making more brittle, lower modulus

whether it is a blend, PC: PBT interact with each other (transesterification)

can you add heat stabilizers, can increase the level of regrind

what kind of shear are you putting into the mix

you won’t try to color match or all bets are off on color stability

Ultem PEI is great, but high heat, I’ve seen >50% regrind work fine, unfilled PP of PE can go a long way with the addition of phosphate/phenol stabilizers.