Mold Building
WPI MOLD has rich experience in making precision plastic mold, over-molding mold, insert molding mold, two-shot molding mold.
Precision Plastic Injection Molding
Plastic injection molding is a process that involves injecting molten plastic into a mold to create different shapes/plastic parts. It is one of the most widely utilized manufacturing processes in the modern world when it comes to mass production of plastic parts.
Plastic injection molding benefits include:
- The flexibility of part design
- The precision with complex design
- Faster mass production
- High strength
The major consideration for making precision injection molds:
- Optimize mold design for all small details
- High precision machining
- Scientific injection molding testing to get the best machine setting.
Over Molding
Over molding, like two-shot molding, is a multi-shot injection molding process that produces a single end product from two or more different thermoplastics.
Over molding benefits include:
- Reduce secondary operation, assembly, and labor costs (Molded as one assembly)
- Improved part strength and structure
- Enhanced design flexibility and multi-material components
- Improved component reliability
The major consideration for making over molding molds:
- Both raw materials need to have good bonding.
- Make sure the first shot part can be held in position when injecting the second shot part.
- Non-sealing surfaces need to consider making a gap with the first shot part to avoid spotting.
- The gate system on the second shot needs to be balanced, otherwise, it is easy to get burs or short shots.
- Make kiss-off sealing instead of shut-off sealing for the second soft material, and consider pre-load for better sealing on the second shot.
- Before making any adjustment to over molding mold, the first shot part need to be dimensionally ok and fix the injection prameters.
Insert Injection Molding
Insert injection molding is the process of molding or forming plastic parts around other non-plastic parts or inserts. The inserted component is most commonly a simple object, such as a thread or rod.
Insert injection molding benefits includes:
- Improved part strength
- Simplify part structure
- Reduces assembly and labor costs
- Reduces the size & weight of the part
- Enhanced design flexibility
- Improves component reliability
The major consideration for making insert injection molds:
- Hold the insert in position with a mechanical structure to avoid moving during the plastic injection.
- The molded insert itself has dimensional tolerance and needs a flexible mold structure to compensate for insert dimension deviations.
Two-shot Injection Molding
Two-shot, also referred to as double-shot, multi-shot and 2K injection molding, is a plastic molding process in which two different plastic resins are molded together in a single machining cycle.
Two-shot injection molding benefits include:
- Part consolidation
- Improved Efficiency
- Improved Quality
- Complex Moldings
The major consideration for making two-shot injection molds:
- Both raw materials need to have good bonding.
- Make sure the first shot part can be held in position when injecting the second shot part.
- Non-sealing surfaces need to consider making a gap with the first shot part to avoid spotting.
- The gate system on the second shot needs to be balanced, otherwise, it is easy to get burs or short shots.
- Make kiss-off sealing instead of shut-off sealing for the second soft material.
- The first shot part shrink will cause bur on the second shot part, need to consider a solution to avoid it before mold manufacturing.
If you have any two-shot injection molding projects, please get in touch with us, our experienced engineer will support you with valued recommendations.
