Computer gong processing mold

1. The height of slide guide rail shall be at least 1 / 3 of that of slide block to ensure the stability and smooth sliding of sliding block.
2. Attention should be paid to the opening of lubricating groove where there is sliding friction. In order to prevent the outflow of lubricating oil, the groove should not be opened into “open type”, but should be “closed type”. Generally, the annular oil storage tank can be directly milled on the milling machine with a single cutter.
3. For the cavity of fixed mold core, the small mold is generally cut by line cutting, which can improve the precision of the mold; while the mold cavity of the larger mold is generally processed in the form of milling, pay attention to its perpendicularity during processing, and in order to prevent the mold core from not in place during assembly, the milling depth should be 0.2mm around the mold frame, and the hole position should be pre drilled on the mold frame at the corner, which will form void avoidance after milling. Prevent the interference of the assembly die (chamfering can also be done on the die).
4. The angle of 1 ° should be added to the interpenetration between the insert and the mold, between the mold core and the mold core, and between the mold core and the mold frame, so as to prevent collision and injury during assembly.
5. The length tolerance and size tolerance of the insertion part are -0.02, -0.10 and + 0.02 respectively.
6. The tolerance from the bottom of the c-angle to the c-angle is + 0.01 to prevent the burring.
7. The main part of the body mould is made of NAK80 material, and the material of skh9 and SKH51 (material treatment: nitriding treatment is also allowed), and Viking material can be used if necessary.
8. After drawing the parts, the position and size of the slider should be determined first to prevent interference and insufficient strength, and then the mold kernel size method should be determined.
9. The tolerance of the size of the insert is – 0.01, and the tolerance of the hole in the mold is + 0. 01 (transition fit).
10. The sharp corner of wire cut square hole on the mold core is excessive with r0.20, and the corresponding entry part is also r0.20, so as to influence the wire diameter during wire cutting, and prevent the sharp corner part from abrasion and edge overflow.
11. The small pit size corresponding to the positioning ball (wave bead) is generally conical hole with bottom diameter of φ 3 and angle of 90 ° to 120 °.
12. The draft angle of the fixed side should be greater than that of the movable side. The high-speed computer gongs can be used to process the mold leaving on the movable side. Moreover, it can prevent the parts from deformation, especially for the parts with thin wall and easy deformation in length, and the uneven pulling force on the fixed side will easily cause the parts to warp or stay on the fixed side.
13. For the parts with large side core pulling force and strict part precision requirements, the secondary core pulling structure should be adopted.
14. The slope of inclined tip + 2 ° = the slope of hold down block (generally 18 ° or 20 ° or 22 °)
15. When assembling molds, the following habits should be formed:

a. Clean the surface of mold core, cavity, runner, runner plate and parting surface with air gun.

b. Before assembly, polish the surface of mold core, mold cavity, insert and parting surface with oilstone to facilitate smooth assembly.

c. Pay attention to the angle cleaning to prevent interference and bruise.

d. Before assembly, we should consider how to carry out the following work.

1. The side pressing block of large mold core should be designed to be locked and the bottom should be 0.5-1.0mm below the parting surface to prevent interference.
2. The shrinkage rate of PC + GF20 is 3 / 1000, and the shrinkage efficiency in the direction of material flow with GF is less than that in the direction of vertical material flow, which is different from other materials.
3. The contraction rate of POM was normal 20 / 1000, but sometimes it was 30 / 1000.
4. In order to prevent the parts from being scratched by the latent gate when the part is ejected, a wedge-shaped block is added 2-4mm away from the latent gate. The height of the wedge is about half of the runner, and the included angle is 10 ° on one side. The gate will be broken when ejected.
5. The main channel pulling well adopts an inverted cone with a depth of 8-10 mm, an included angle of 10 ° on one side, and a top diameter of a wide flow channel. The advantage of this method is that it can prevent the pulling material from one side grinding into a wedge shape from hooking the flow channel during ejection, resulting in poor parting.

There are two kinds of opening and closing devices: 1. Made of rubber, the deformation is adjusted by the central screw to adjust the tension. 2. Made of spring steel. Their functions are: delay the opening time of movable side and fixed side, apply to small nozzle mold (three plate mold) or apply to secondary ejection system.

1. In order to ensure whether the ejector pin and inclined pin of the mold are reset, some molds are equipped with early return mechanism (female is installed on 108 plate, male is installed on 102 plate, male is similar to thimble, the bottom is blocked with headless screw, and two are generally arranged) or microswitch (between 108 and 109 boards [power mounting element]).
2. Considering the screw length of the injection molding machine when clamping the mold, it is necessary to pay attention to the thickness of the upper and lower fixing plates (generally about 40mm). If necessary, the four corners should be milled lower. At the same time, in order to improve the safety, four bolt holes can be drilled on the upper and lower fixed plates according to the position of the upper holes of the injection molding machine.
3. The forming end of the oblique pin has a straight face, which is generally 4-6mm long. In order to slide the inclined pin between 107 and 108 plates during ejection, an R angle of 0.5mm-1mm should be poured at the bottom.
4. For the appearance that needs to be bitten, the degree of biting should be considered in the design of draft angle, so as to avoid the appearance strain. For some protruding parts, the cross-section will become larger after biting, so the single side should be 0.02-0.03 smaller in actual processing.
5. Considering that the mold closing between the fixed side and the movable side will result in break, the fixed side is 0.03-0.05 smaller than that of the movable side.
6. In the mould with sliding block, sometimes it is necessary to set oil groove on the inclined surface of the sliding block and the pressing block; in addition, if the forming is not affected, the processing efficiency of opening oil groove on the upper surface of the template is higher than that on the bottom of the sliding block.
7. The parting surface should not be selected at the required position of the surface.
8. The shrinkage of the fiber with fiber is 1-2% smaller than that of the flow direction, which is larger than that perpendicular to the flow direction; otherwise, it is the opposite.
9. The shrinkage rate of the addendum circle is 1-2 thousandth less than that of the root circle.
10. When the die is used for a section