First of all, a basic question, what is cost of mold, many people think that cost of mold is mold material fee + processing fee + tax, of course, labor and design fees, but we can think that labor cost include in processing fee.
From a narrow point of view, this answer is good, but if it is only this, then in addition to cutting corners and tax evasion, is there any way to control or reduce costs?
Therefore, to really talk about cost of controlling molds, we must analyze various factors that affect cost of mold.
Cost of Mold – Rational design of product
Whether design of product is reasonable or not is the biggest factor affecting cost of mold. Our company engage in mold for more than 20 years. This kind of thing has experienced a lot. Sometimes, in order to achieve an undercut on product, product engineer and mold designer do not communicate well, and cost of mold will increase exponentially.
Our company has taken over design of a car accessories company for a disabled person in Germany. One of parts is call middle partition. According to original design, this part is very large. Manufacturing cost of mold is about 4 million RMB, and matching injection molding machine is more than 4,000 tons. However, customer splits it into two pieces with a new design, and production cost of two sets of molds does not add up to more than 2 million. Matching injection molding machines are all 1,500 tons.
Therefore, a product designer should try to understand knowledge of mold as much as possible, so that designed product is as suitable as possible for mold engineering, and do not increase difficulty and cost of mold. Under premise of meeting assembly of vehicle, maintaining good communication with mold department is the most effective and direct measure to reduce cost of mold.
There is also a philosophical question of productivity and production relations. Some product engineers believe that cost of mold is a matter for your mold company and has nothing to do with me. However, if production relationship recombine, injection molding company and mold company are one, what will happen? In fact, this is a social trend. Companies that are operating better now are combination of injection molding company and mold company. One company that exists solely on basis of making molds can hardly survive.
Cost of Mold – Product design changes
Mold company often encounter such a situation. In a certain project, mold has just design, mold frame has just order back, and customer’s change notice will come. If it is a small change, it will not affect overall structure of mold. It doesn’t matter, sometimes it’s more serious, because shape of product changes, mechanism needs to be add to mold, and even mold base must be reorder. This cost has increased. So try to minimize design changes. There are a lot of rapid prototyping methods. Before mold is made, 3D of rapid prototyping will be used to make whole vehicle assembly, and 3D of product can be corrected in time to minimize cost increase caused by product design change.
Whether mold design is perfect
Here are two situations to analyze:
First is rationality and processability of mold design.
In general mold companies, there must be old and experience designers in design team, as well as young engineers who have just come out of school. We can’t ask young engineers to design high-level molds independently when they first come to company. Experienced mold engineers, if mold structure produced by closed doors can not be perfect, there will definitely be some inconspicuous details, so one of the most important and effective methods is collective review. I believe that everyone has a consensus on this issue. There are now many simulation methods, such as mold flow analysis, mold structure dynamic analysis, trial products and design 3D comparison analysis, mold flow analysis,which can minimize cost increase caused by irrational mold design.
Second case is mold design waste. If mold user clearly produces 500 samples as long as mold is use to develop market, if we design according to mold with a life of 300,000 molds, cost will be large, which is a waste of design.
Try to reduce number of trials of mold
Many mold companies calculate processing cost of mold, and calculate processing fee based on number of days after receives order and product is qualified. If mold can not be deliver after repeated trials, except for penalty according to contract. The more days mold is in factory, the more processing costs. Of course, cost of mold trial is also very considerable. Therefore, multiple or uncontrollable mold trial times is a large blind spot for mold cost control.
Let’s analyze reasons why number of mold trial is too many.
The first is that mold design has not undergone sufficient collective review, and mold structure is unreasonable. So that mold has to undergo many improvements after test, so that mold cost exceeds budget.
If after several improvements, you can get it. It is fortunate. There are many cases that are unsatisfactory. Even if mold is to scrap and rework, cost cannot control. There are also some cases where mold design is very good, but processing of mold is not in place, which makes number of trials increase without any reason, directly increasing cost of mold. There is no objection to this problem, so many mold companies have increased their investment in measuring equipment.
Second is that model is not selected for the best molding process and model of injection molding machine. Mold well made, but injection molded product not ideal. Number of trials increase without any reason, which directly increases cost of mold. This is a common problem in some small mold factories.
Third is that there is not a sufficient understanding of physical properties of plastics, and even shrinkage rate is not accurate. Such a situation occurs from time to time. Therefore, before designing mold, it is necessary to understand physical properties of plastic, in order to effectively reduce number of trials.
Mold materials and standard parts procurement
Choose a stable, reputable supplier. It is a pity if mold is out of order because of greed and sloppy purchase. This is actually a lot of things. Although responsibility of supplier can be investigated, the biggest loss is mold company and mold user.
Product is qualified
If we say, we used 100,000 yuan to request a mold for a car glove box. Plastic used is PA+30% GF, injection cycle is 30 seconds, and die life is 300,000. As a result, mold of car glove box made, size and physical properties of sample achieved. However, because injection was difficult during injection, injection cycle took 60 seconds, and could not use mold production of 100,000 pieces, in order to catch up with vehicle. Must cast mold again. According to original mold situation, it is necessary to cast 3 sets of molds at once. It is also spending so much money, I think cost of this set of molds is three times or six times original budget. Do you have a different opinion for control cost of mold?
In summary, in order to effectively control cost of mold, it must be done:
Reasonable product design, minimal design changes, perfect mold design and processing flow, good communication between product engineers and mold engineers.