New structure of classic front mold stripping thread and rear mold lifter
Time:2023-09-09 19:21:04 / Popularity: / Source:
Product glue feeding method
There are many kinds of product glue feeding methods, such as bottom glue feeding, submerged glue feeding, direct gate, corner glue feeding, point glue feeding, etc. Since back mold of this product is not easy to feed glue, it adopts hot runner to cold runner (submerged glue feeding). Submerged glue feeding can submerge front mold, rear mold, thimble, and bone position. This set of molds adopts glue feeding method of diving into front mold, as shown in figure below:In order to facilitate processing, front mold inserts are inserted separately
There are many glue positions on the front mold inserts. Cooling glue position is designed to transport water in a spiral on insert, as shown in figure below:Design of rack and pinion mechanism
Pay attention to design of rack and pinion structure. Pressure angle of national standard gear is 20 degrees. Modulus of the two gears must be equal so that two gears can mesh normally. When designing structure, a brace is also designed. Number of turns of gear is related to number of turns of screw teeth of product. When designing, it must be noted that number of rotations of gear (circumference) is equal to distance from rack, otherwise gear will be easily pulled off, as shown in figure below:Inner buckle of rear mold adopts an ordinary lifter structure
When designing lifter, attention should be paid to angle range (3-12) degrees of lifter. Material of lifter is generally H13 or 1.2344. Lifter needs heat treatment: it is generally hardened to (48-52) HRC, and surface of lifter needs to be nitrided. Due to limited space, angle of four lifters is designed to be 3 degrees, and fixing method of bolt is adopted. When matching mold, it is necessary to install four lifters in rear mold core to save mold together.Pay attention when designing lifter seat
Due to limitation of space, lifter seat adopts mosaic structure, which is divided along direction of 45 degrees, and lifter seat is designed as a guide chute, which is convenient for processing. Each lifter seat can be processed directly by wire cutting, which saves space. Disadvantage is that it increases workload of fitter for mold matching. Fixing method of lifter seat: use screws to fix it on thimble bottom plate, as shown in figure below:Movement principle
When mold is opened, oil cylinder drives rack to move. Rack hangs on oil cylinder through T-block, rack drives pinion to rotate, pinion and big gear are connected together through bearings. When big green gear rotates, it will drive tooth gear of product to rotate together, so as to achieve effect of product thread removal. When product thread comes out, product remains in rear mold. At this time, ejector pin moves ejector plate through ejector hole, driving lifter of rear mold to move upward together. At this time, product is ejected out of mold, as shown in following figure:Heat distortion thermometer for common plastics
Heat distortion temperature | |||
Heat deflection temperature (low pressure) | ASTM D 648 | Heat Deflection Temperature (High Pressure) | ASTM D 648 |
Variety | °C | Variety | °C |
PET | 67 | Polyester Elastomer | 49 |
ETG | 70 | PET | 62 |
PVC | 70 | PETG | 64 |
PCTA | 73 | PA | 65 |
PCTG | 74 | PCTA | 65 |
CA | 81 | PCTG | 65 |
K-RESIN | 85 | Homo-polymer PP | 65 |
CAB | 85 | PVC | 67 |
CAP | 88 | Flame Retardant PP | 70 |
CLEAR ABS | 89 | High Heat Resistance PP | 70 |
Polyster Elastomer | 90 | CA | 71 |
m-PPO | 92 | CAB | 74 |
SAN | 92 | PA 66 | 75 |
gABS | 95 | K-RESIN | 77 |
ACRYLIC | 99 | CAP | 78 |
PC/ABS | 104 | m-PPO | 80 |
Homo-polymer PP | 105 | SAN | 80 |
Flame Retardant PP | 110 | CLEAR ABS | 83 |
High Heat Resistance PP | 135 | ABS | 84 |
PC | 138 | ACRYLIC | 91 |
POM(Co-) | 160 | PC/ABS | 95 |
PP+30%GF | 165 | POM(Co-) | 110 |
POM(Homo-) | 170 | POM(Homo-) | 124 |
PSU | 179 | PC | 131 |
PA 6 | 180 | PP+30%GF | 155 |
PES | 208 | PSU | 167 |
PBT+20%GF | 217 | PBT+20%GF | 193 |
PA 66 | 220 | PBT+30%GF | 195 |
PBT+30%GF | 220 | PES | 195 |
PET+30%GF | 239 | PCTA+15%GF | 202 |
PA66+13%GF | 240 | PET+30%GF | 217 |
PA66+33%GF | 250 | PA66+13%GF | 230 |
PCTA+15%GF | 259 | PA66+33%GF | 245 |
PPS | 260 | PCT+30%GF | 247 |
LCP+30%GF | 265 | PPS | 260 |
PCT+30%GF | 275 | LCP+30%GF | 265 |
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