Custom PMMA Plastic Injection DME High Precision Mold UV Printing
Custom PMMA Plastic Injection DME High Precision Mold UV Printing
High Light：DME High Precision Mold, PMMA High Precision Mold, DME High Precision Injection Molding
Mould Material：S136 Steel 1.2324
Product Material：ABS,PP,PC,PA,PMMA,PS,POM And Etc
Mould Base：HASCO,DME
Mould Life：100,000 Shots-1,000,000 Shots
Mould Runner：Hot Runner/cold Runner
Surface Finishing：Polishing / Mirror Finishing/UV Printing/Electroplate
Place of Origin：Shenzhen , China
Brand Name：OEM/ODM
Certification：ISO 9001 : 2015 , CE
Model Number：81928 C15KCHD
Minimum Order Quantity：plastic :3000 Pcs;mould:1 set
Price：Negotiate
Packaging Details：Carton and Wooden
Delivery Time：30 Working Days
Payment Terms：T/T, L/C, Western Union
Supply Ability：plastic :200000 Pieces Per Month;mould:20 sets Per Month
warpage
When plastic material is injected into a mold cavity, it is cooled and solidifies to form a part that is made to final part dimensions. However, if the cooling of this part in the mold is not uniform differences in part shrinkage can occur, causing the part to distort. This condition is referred to in the injection molding industry as warpage. Warpage is also the result of excessive stresses that are built into a part during the molding process.
Causes
1. An injection speed that is too fast will increase the melt temperature, forcing the melt to overpack the cavity. This overpacking creates molded-in stresses in the part, which warp the part.
2. The injection speed is too slow, the viscosity of the material increases the amount of packing pressure needed to fill the cavity. This higher packing pressure adds molded-in stresses in the part, causing warpage.
3. Long injection forward times contribute to part warpage by allowing more time for more material to overpack the cavity.
4. Check ring wear can cause shot-to-shot consistency, creating overpacked parts.
5. If the gate has not sealed off before the cavity is full, overpacking occurs causing warpage.
6. If not enough gates are used to fill a part, higher packing pressures occur to ill out the part, producing molded-in stresses.
7. Smaller gate sizes cause a high degree of molecular orientation in the polymer that causes different shrinkage in different directions of the part (machine vs transverse).
8. Insufficient cooling times do not provide enough time for the part to cool, Increasing shrinkage.
9. Running the mold halves at different temperatures can cause shrinkage in one direction to help overall warpage. Parts have a tendency to warp toward hotter mold halves since this causes higher shrinkage.
10. If ejection forces are uneven due to ejector pin placement or length stresses can be induced in the part causing warpage.
11. Differences in wall thickness promote warpage since thin sections cool faster. thicker sections cool slower.
12. Sharp corners can promote molded-in stresses that can cause warpage
Solutions.
1. Decreasing the melt temperature if the injection speed is too fast.
2. Increasing the injection speed to decrease the holding pressure needed to fill the cavity.
3. Limiting the injection forward time.
4. Replacing check ring.
5. The gate seal needs to be measured to assure that the cavity is not full before gate seal takes place.
6. Increasing the number of gates reduces the packing pressure by distributing the pressure over a number of gates.
7. Larger gate sizes reduce orientation.
8. Increasing cooling time or fixturing the part are options to prevent the part from distorting.
9. Location and placement of cooling lines should be reviewed to ensure that even efficient cooling is taking place to the part.
10. Improving or modifying pin design can reduce part warpage.
11. Uniform wall thickness helps avoid warpage Issues.
12. Removing sharp corners can reduce molded-in stresses and reduce stresses that can be caused during part ejection.
