Home » Plastic Injection Molding in China
As having been the Asian tooling manager for a prominent US company for the past 15 years I can attest to numerous hot runner problems. Most hot runner problems resulted from the hot runner/injection mold system going through revisions in material (resin) changes which had significant effects on the basic design of the hot runner delivery system and components. This is why I suggest that in a high volume application, it is wise to validate a part design using a conventional drop mold before diving into a costly hot runner manifold. There are dozens of hot runner manufacturers in China alone, the Good, Bad and the Ugly. If the cost is the main driver of supplier selection----Good Luck !!! If however you have a part/program that deserves a quality hot runner system, which affords you the technical and field service support, your choices are few, and this would be based on the injection molding location. Sure there are single "Hot Drop" components that fill the need of many applications and are quality products, but I don't consider these products to be a substitute for multi-gate hot runner manifolds, nor do they serve the same purpose.
In my opinion, there are several reasons for Chinese mold makers like to use fake material to make molds:
  • No industrial standard for mold. The governments have no interesting to improve mold industry, just care about their tax income.
  • The cost of punishment is too low to mold supplier to use fake material. In China, this situation is very bad. Even the foods are made from bad or fake raw material. The governments few punish the fake things maker, if the bad thing not threaten the social stable. They do not concern that if the fake material mold damage abroad clients' interest. On the mold maker side, what their lost is only a client, no body to punish them. It seems like Zero risk to use fake material to make fake material mold. It is luck to meet a serious mold maker in China.
  • The buyer should believe that what you get is what you pay. Sometimes lower price is unreal.
We paid high school fees as you call it for faulty/inferior molds from China. The only way to deal with a Chinese mold maker is to specify the grade of material you want, shore hardness, heat treatment and certification on the quality of steel on the molds. The guarantee from any company in China is not worth the paper it is written on, unless you are willing to ship any product back and forth to China at your own cost for repairs.

Get tool drawings first and get a qualified designer to check them and accept. On completion of mold do a minimum production run of 3 days and see the quality of the product. If you are happy with what you have then get them to strip the mold and check for any wear and tear on mating surfaces. If this is ok then purchase it and the production run. Trust me this is the only way as I am still recovering from the financial loss from 10 years ago. This is what we do now and it seems to work.
Not being in the injection molding industry, I was looking for tips on how to judge a company or factory on their capability or capacity to do a particular job. In China, everyone is a molder. However, I have noticed that if you ask people as to their ability to hold certain tolerances, they will be truthful about it.Injection molding factory I am not saying that they will be able to produce plastic parts even to tolerance levels they clam, but I think that eliminates probably 90% of people who may respond. I still have to go into it deeper, obviously, but it is a start. So visit to a factory is an absolute necessity. My problem is that my plastic parts are very thin, with a profile on o.d. and I don't know many plastic molders, and certainly any capable of doing these plastic parts. In addition, these are reverse engineered parts, and not being able to lay my hands on spares I am trying to keep my tolerances as close as possible to avoid problems with tolerances. So at this time I am just trying to develop a list of companies that think they can make my custom plastic parts by sending them drawings. If they say can do this and provide tolerance level they feel comfortable with, I ask them for an RFQ. I will then follow up with a tour.
But I believe the best way might be to make a small injection mold to test their ability, just to keep my exposure as low as possible and test the plastic molder.
Current situation live in China...US plastic injection molding company scheduled staff in China for 6 days of mold trials beginning February 4. Tooling fixtures and components necessary to run the plastic injection mold trials are stuck in customs and customs is demanding >25% of value of these components to release them. My previous experience has been 17% import duties/taxes (regardless, delays are not uncommon if you are not familiar with the paperwork necessary to make a successful clearance).

This is only one example of hidden costs, more obscure than some mentioned above. If I was managing a plastic injection mold build project, I would have to take a look at the big picture regarding China or America. If it was a one-time deal, I would manage the plastic injection mold project through a reputable broker in the US. In this way I can be confident with TOTAL costs up front and avoid the agony of putting up a number to my customer for the price of the plastic injection mold project and then watching my margin slowly erode as the build progresses.
Many companies I deal with see a plastic injection mold tooling quote and never add in the "extras".
I have been sourcing plastic injection molds from China for over 15 years and here is my list of concerns buyers have mentioned.
  1. What is the real landed price to my factory.
  2. Understanding that the PO is for good parts/tool to run to EAU for X years not just samples.
  3. Who covers all the freight cost for samples sent from China.
  4. Are components used in injection mold tooling available in US.
  5. Does PO for tooling include all CAD files required to make domestic plastic injection mold changes.
  6. Are CAD files updated to reflect the actually injection mold tooling being shipped.
  7. Was the plastic mold tooling sampled in an equivalent machine to the one it will run in in the US.
  8. Did the plastic injection mold run for 24 hours or just long enough to get enough samples.
  9. Did you receive parts on the runner and not groomed, that will tell you a lot about what injection mold is being shipped to you.
I have met so much the plastic injection mold manufacturers in South and East China. But the problems are following:
1) In China the workers want to earn the money and the owner want also earn the money in the short time. So you could not easy to find some good worker, who could do the job for many years. If the owner find out they could not earn so much money, they could invest in other area.
2) There are really the different culture between China and West. If you find in other country, you will find such different in India, which make also injection mold business, and South Korea. I think the reason is, how long the injection mold industry could be developing in the country. If the total mold industry would be developed so good, you will find actually there are no so much different.
3) About the price. Why the customer in EU and USA buy injection molds in China or India, South Korea. Only because the price. The most of them do not calculate what behind such low price. If you only want to buy such mold with low price, you must accept the quality. Just like you in EU and USA.
4) Some company could also make very good plastic injection molds, but the price for some companies from EU and USA could not accept them. And the owner would also like to get big order.
I respect what China has done to provide tools to allow their people to manufacture, forging, die casting, metal stamping, or injection molding. Any nation that loses its ability to manufacture loses control over their destiny. In NA we are feeling this right now, young people have no factory jobs, middle management in manufacturer does not exist, and taxes are not being collected for governments. The purchasing power of the average person has been diminished, forcing the average person to buy the cheapest products at the retail level- made in China. The end result is a downward spiral of recession bordering on recession/depression. It is time for NA to impose VAT on all imported goods to level the playing field.

China is now out sourcing injection molding to other low cost countries because your people are demanding fair wages for an hour of labour. It will stop one day, in the meantime many will suffer just to make a few more points profit. Again I challenge all countries to embrace a fair global minimum wage, just like a sports game with the same rules for all.
I have been making injection molds in China for 15 years or so. Honestly, China has never had the quality of molds that other USA, or German shops have always had. You get an injection mold capable of making a good part that meets dimensions in China, but will constantly be under repair in China.

It is hardly to find any good plastic mold maker as good Europe, Japan or USA. It is very much depends on how you want your product to be defined. If it is high precision product requests stringent tolerance control, just go to these 3 regions. If you are looking for a good finishing and reliable injection mold, which mainly for cosmetic (casing, housing part etc...) you can make this kind of mold vender in Malaysia or Singapore. They bring you less reliability problem as compare to the Chinese. Of course, you still can find a good injection mold maker in China.
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