According to our factory status, I think the main reasons are as follows:
*Is the mold good or not?
As you know, plastic products are made from molds. So, the mold quality will affect the product quality.
The mold material has different types; for example, P20 and 718 are steel types. The different mold materials and processes cause mold prices to have significant differences.
We once had a cheap mold for a product. But it causes a lot of problems for the products. We saved the costs of molds but paid more time and extra money for the mold fix. Meantime, our customers complained about the product quality.
*Does your machine engineer do good work?
A good machine engineer will help you to save production time and money.
Many people work as machine engineers, But their techniques have significant differences.
The engineer initially controls the product quality, for example, colors, flash, and weight. They should know how to adjust the machine to match molds and materials.
*Needs workers have a high responsibility.
Even if molds have no problem and the engineer sets the machine in good condition, It is still possible for the product to have problems in production. So, we need the workers to have a high responsibility. They are the first person to see the product if they can find the problem and report it to the engineer, who will fix the problem first.
Except for the machine workers, the packing workers and the quality checkers also need to pay attention to the product.
But, if we can fix the most quality problems in the production stage, we will save quality check time in the packing period.