Making of injection molded components involves several steps, which must be executed with precision to achieve the expected level of quality. However, how much ever the service providers try, there is a room for expensive errors when it comes to the injection molding process. Some of such errors would be unrepairable, leading to material wastage and loss of money. However, several of the injection molding issues can be rectified by properly executing several troubleshooting tips.
Troubleshooting, which is an art and science of remedying defects, helps avoid common problems encountered during the process of injection molding. This post discusses ways to troubleshoot injection molding problems and their remedies.Troubleshooting Injection Molding Issues: Problems, Causes and Remedies
When it comes to injection molding process, certain defects are unavoidable, which in turn put the entire production in trouble. The following are a few amongst the several defects with their causes and troubleshooting tips.
- Blisters or bulge on the surface of the part.
- Foreign objects/contamination
- Mold temperature out of spec
- Improper vacuum
- Tool deflection
- Faster oven temperature heat-up rate
- Check the material used for the process thoroughly for any kind of contamination.
- Increase the mold temperature adequately.
- Set appropriate vacuum.
- Check for mold deflection.
- Chip: (This results in small missing of pieces).
- Rough handling and bypass
- Improper secondary fixtures
- Monitor part quality at every stage
- Decrease molding pressure
- Polish the tool surface at regular intervals
- Ensure proper handling while shipping
- Flow Lines (streaks, patterns, or lines)
- Variations in the cooling speed
- Different speed at which the molten plastic flows
- Molten plastic flows through sections with varying wall thickness
- Too low injection speed
- Increase injection speed and pressure
- Round the corners of the mold
- Burn Marks(black or rust-colored discoloration on the part surface or edges)
- Trapped air
- Overheating resins in the mold cavity
- Excessive injection speeds
- Decrease the mold temperature
- Minimize the injection speed
- Enlarge gas vents and gates, so that the trapped air leaves from the mold
- Dull Surface or Gloss Surface
- High shrinkage of the material
- Loss of pressure
- Unacceptable tool surface
- Choose different shrink additives or levels
- Increase mold temperature, cure cycle and molding pressure
- Polish the surface of the tool
- Part Deformation
- Too short aftertime pressure
- Defects in the heating process
- Too low injection pressure
- Increase injection pressure, mold surface temperature and cooling time
- Decrease regrind percentage, whilst also increasing gate diameter.
- Smudges
- Matt surface
- Stringing in the gate area
- Gate blush
- Haziness
- Vacuum voids / air pockets
- Poor appearance
- Short shot
- Black specks or discoloration
Causes: There are several reasons that lead to blisters on injection molded parts. A few amongst them include:
Remedies: Implement the following troubleshooting techniques to avoid blisters on your parts.
A few other techniques you can try in case of blisters include the use of less reactive catalyst, increase material flow distance, set appropriate mold temperatures and cure time, among others.
Causes: Usually occurs near the edges of the part, this defect can be caused due to the following reasons:
Remedies: What can you do in case you come across chip on the part? Check out the following troubleshooting tips.
You can also try to conduct preventative maintenance procedures on molds and fixtures, increase compound viscosity and slow ejector speed to avoid the formation of chip on the part.
Causes: This defect is mainly caused due to the following:
Remedies: Flow lines, which appear as a wavy pattern, can be avoided by implementing the following troubleshooting tips.
Injection molding is a lengthy process, which requires attention to fine details. Any flaw in the procedure results in defective components. However, certain defects in the process are unavoidable. But, the injection molding service provider can limit these risks by implementing the right troubleshooting techniques. So far, we have listed three amongst the several injection molding issues.
Causes: The reasons for burn marks are as follow:
Remedies: With the implementation of the following troubleshooting tips, burn marks can be avoided to a great extent.
Causes: There are several reasons for the formation of a dull surface on the part, which are as follow:
Remedies: The following are the tips the injection molding service providers usually implement to nullify the problem of dull surface.
Causes: The part deformation is a result of the following;
Remedies: To avoid the production of deformed parts, the injection molders can implement the following:
Rather than these common injection molding issues, there are several more defects that commonly occur during the creation of plastic components. They are listed as follow:
Most of such defects can be avoided by implementing the specified troubleshooting techniques. By troubleshooting injection molding problems effectively, you can not only save money and time, but also minimize material wastage. Hence, injection molded part manufacturers must be aware of such techniques, which in turn helps producing parts without defects as specified by the customers. All the leading injection molding companies like Veejay Plastic are well versed with such troubleshooting techniques and they wisely use them at the right time when producing plastic components. Such techniques largely enable them to produce high quality parts without flaws.
