iMoldX-Case Story_02 Plastic Product Re-design

Here is typical story happened between us and one of our customers, Mr. David Guasca, a purchase manager from UAS.
Mr. David Guasca's company is a global leader in the delivery of robust, reliable and advanced RF wireless systems,
networks and solutions for the fast-growing M2M industry. For the first time he wanted us to quote an electronic enclosure
for him, and he wanted to make mass production in our factory.

1. Product Name: a plastic enclosure for an electronic product
2. Product Material: CHIMEI PC/ABS (PC-510) (UL94V-0)
3. Product Gross Dimension: 140 L X 85 W X 45 H mm ( after assembly)
4. Initial order quantity: 10000 pcs.
5. Mold Demand
5.1. to make injection molds with 0.5 million shots lifespan.
5.2. cacity/core No.: NA

When we made the quote for him, we also pointed out that there were many points in the enclosure configuration that had to
be improved further. Soon after our quote, he placed order with us and also asked us to improve the enclosure.
Below were the points that we improved for him.

After we improved the configuration of these parts, we sent improved 3D files to him and asked him to confirm them.
There was an episode when his designer confirmed our improvement on the enclosure. He did not agree to modify one of the undercuts. We asked him to re-design this undercut, and then he designed another undercut. We also had to improve this undercut for him and asked him to confirm it again. But he still did not agree. The process of improvement on this undercut was repeated up to five times, and at last we found a compromise solution to this undercut problem that both the designer and we could accept.

There were two plastic injection molds for the six plastic parts altogether: one was for the top cover and the body of the
enclosure, and the other was for the other four parts. The big mold for the top cover and body was a 3-plate mold, with a long core insert for the boy, three slides and three lifters. All the cavity/core steel is NAK80 so that the mold lifespan is guaranteed.

The construction of the two molds was finished in 35 days after we got the approval of the improved 3D files from the designer. Then we made T1. All the injection parts were OK except for only one problem: the plastic body stuck to the cavity when the mold was ejected and it was not easy for the body to be moved from the core!
We checked the problem and found that the texture of the exterior of the body was "YS20004A", a very rough texture, but in the internal surface of the body, there was not any texture and only a technical polishing layer. Because roughness of the two surfaces of the body exterior and interior was not the same, the forces of their surface friction were different. So the body stuck to the cavity when the mold was ejected.

We suggested to the designer that the same texture "YS20002A", a smaller one than"YS20004A", should be made on the both surfaces of the interior and exterior so that the previous different forces of the surface friction would be also smaller, and more important, they were the same force. The designer agreed and the problem was solved in this way.

Soon, the plastic samples were produced and sent to David for approval. But after he got the samples, his designer found that several points were too loose after assembly, and asked us to add some plastic materials to those loose points shown as below.

We improved the molds as per the designer's demands and made the second samples for approval. But after he got the second samples, he thought that the snap system of the battle base and battle locker was still too loose. He sent us improved 3D files of the two parts and asked us to improve them further. We checked his improved 3D files and found that the snap width is still too small (2.0mm), and the elasticity of such a small snap is not big enough. But we had no idea of how wide it should be. We asked the designer for this information and he told us that he also did not know this.

To solve this problem, we designed three solutions: 2mm, 2.5mm and 3mm, and we also made three prototypes for them to choose a proper width so as to avoid imporving the mold again and again. The designer agreed.

After he receieved the prototypes, Mr. David Guascar's designer confirmed that the 2.5 mm solution is the best one.
We improved the mold for the second time and made the third samples soon. This time the third samples were all OK and we got approval of the final samples David at last.

Case Story #02: Plastic Product Re-design