Problem solving
Problem | Solutions |
|---|---|
Short shots | ↑ Injection pressure ↑ Injection speed ↑ Melt temperature ↑ Mold temperature |
Part warpage | ↓ Mold temperature ↓ Injection speed ↓ Injection pressure Modify overall cycle time |
Sticking cavity | ↓ Injection pressure ↓ Mold temperature ↓ Screw forward time Modify overall cycle time |
Sticking, Sprue | ↑ Nozzle temperature ↑ Nozzle temperature ↓ Injection pressure ↓ Mold temperature |
Flash | ↓ Injection pressure ↓ Melt temperature ↓ screw forward time ↓ Injection speed |
Oversized parts | ↓ Injection pressure ↓ Injection speed ↑ Melt temperature ↑ Mold temperature |
Undersized parts | ↑ Injection speed ↑ Injection pressure ↑ Screw forward time ↓ Melt time |
Burn marks | ↓ Melt temperature ↓ Injection speed ↑ Vent size Modify overall cycle time |
Sink marks | ↑ Injection pressure ↓ Injection speed ↑ Screw forward time ↑ Mold temperature |
Streaking | ↓ Injection pressure ↑ Mold temperature ↑ Melt temperature Predry resin |
| Material type | Drying parameters | Zone temperatures | Nozzle | Mold | |||
|---|---|---|---|---|---|---|---|
| Material type | Temp.F | Temp.Hr | Front | Middle | Rear | Temp.F | Temp.F |
| ABS | 175-190 | 2-4 | 400-490 | 380-450 | 360-410 | 390-450 | 120-200 |
| Acetal | 180-190 | 1-3 | 350-400 | 350-400 | 310-470 | 350-400 | 180-250 |
| Acrylic | 170-200 | 2-4 | 430-480 | 430-480 | 440-500 | 430-590 | 150-200 |
| Nylon 6/6 | 160-220 | 2-6 | 530-560 | 520-550 | 510-540 | 510-550 | 130-190 |
| Polycarbonate | 230-260 | 3-4 | 530-590 | 500-560 | 500-560 | 530-610 | 160-230 |
| Polyester | 250-275 | 2-4 | 490-520 | 470-510 | 460-500 | 500-570 | 180-250 |
| Polypropylene | 180-210 | 1-2 | 380-450 | 350-450 | 350-450 | 350-450 | 60-200 |
| Polystyrene | 150-190 | 1-3 | 375-450 | 350-425 | 350-425 | 350-400 | 80-120 |
| Polytethylene | 150-170 | 1-2 | 350-400 | 350-400 | 320-370 | 350-425 | 70-100 |
| Polyeurethane | 180-220 | 2-4 | 350-440 | 360-420 | 350-400 | 420-460 | 80-200 |
| PVC | 150-180 | 2-4 | 320-370 | 330-360 | 280-320 | 330-370 | 100-150 |
| Test | Definition | Units English/Metric | ASTM Test | |
|---|---|---|---|---|
| Brittle Temperature | A measure of materials for low temperature flexing or impact | °F °C | D746 | |
| Continuous Service Temperature | The highest temperature at which a material can perform reliably in a long term application | °F °C | ||
| Deflection Temperature 66 lb/in\u00B2 | The measure of temperature at which a specimen detects 0.01 inches under a load of 66 lb/in\u00B2. | °F °C | D648 | |
| Deflection Temperature 264 lb/in\u00B2 | The measure of temperature at which a specimen deflects 0.01 inches under a load of 264 lb/in\u00B2 | °F °C | D648 | |
| Density | The equivalent property to specific gravity;measured by displacement relative to water | lb/ft\u00B2 g/cm\u00B2 | D792 | |
| Dielectric Strength | The voltage that an insulat¬ing matieral can withstand before dielectric breakdown occurs. | V/10\u00B3inV/mm | D149 | |
| Elongation Break | The increase in distance between two gauge marks at the break point divided by the onginal distance between the marks A zero value in the Field indicates that it measured less than one | % | D638 | |
| Elongation Yield | The increase in distance between two gauge marks at the yield point divided by the onginal distance between the marks A zero value in the Field indicates that it measured less than one | % | D638 | |
| Flexural Modulus | The ratio within the elastic limit of the applied stress on a test specimen in fissure to the corresponding strain in the outermost fibers of the specimen | lb/in\u00B2 kg/cm\u00B2 | D790 | |
| Flexural Stength Yield | The measure of resistance of the material to fracture during bending. | lb/in\u00B2 kg/cm\u00B2 | D638 | |
| Hardness | The resistance of a material to compression | indentation and scratching. | ||
| izod Notched LT | The energy required to break a specimen in which there is a v-notch to create an initial stress point but measured at low temperature (-40°C). | ft/lb/in/kg cm/cm | D256 | |
| lzod Notched RT | The energy required to break specimens where there is a v-notch to create an initial stress pc.iint. | ft/lb/in/kg cm/cm | D256 | |
| Linear Mold Shrinkage | The difference between the size of the part and the size of the mold cavity Values given are often the average of a range. | in/in | D955 | |
| Linear Thermal Expansion | The fractional change in length of a material for a unit change in temperature. | in/in °F cm/cm °C | D696 | |
| Melt Flow | Rate of Extrusion of molten resin through a die of a specified lenth and diameter | g/10min | D1238 | |
| Tensile Modulus | The ratio of nominal stess to the corresponding strain below the proportional limit of a material. | lb/in\u00B2 kg/cm\u00B2 | D638 | |
| Tensile Strength Break | The maximum stress that a material can withstand without breaking when subjected to a stretching load. | lb/in\u00B2 kg/cm\u00B2 | D638 | |
| Thermal Conductivity | The rate of heat Now under steady state conditions through the unit area per unit temperature gradient in a direction perpendicular to an isothermal surface | BTUin ca/cm/\n hr ft2 °F see cm\u00B2 °C | C177 | |
| vicar Softening Point | The temperature at which a fiat ended needle will penetrate a specimen under a specified load using a uniform rate of temperature rise. | °F °C | D1525 |