For example, small gates such as tubular gates cool much faster than tapered gates. For molding workers, adjusting the processing conditions is one way to solve the shrinkage problem. Filling pressure and time significantly affect shrinkage. In fact, for the demanding products such as household electrical appliances, the shrinkage marks must be eliminated, and for products such as toys that have low surface quality requirements, shrinkage marks are allowed. There may be one or more reasons for the formation of shrink marks, including processing methods, component geometries, material selection, and mold design. In the thicker position of the plastic mold parts of the Huangjiang, such as the ribs or protrusions, the shrinkage is more serious than the adjacent position, because the cooling rate of the thicker area is much slower than the surrounding area.

Cooling runner design, gate type, gate size can have multiple effects. Shrinkage is a stubborn disease.. Premature cooling at the gate reduces the fill time in the cavity, which increases the chance of shrink marks. The difference in cooling rate causes a depression at the joint surface, which is a familiar shrinkage mark. This method may not reduce the shrinkage marks to a satisfactory level by itself, but the molder can adjust the filling conditions to improve the chair mould manufacturers shrinkage marks.How to reduce shrinkage in plastic mold processing?

How to reduce shrinkage in plastic mold processing? Shrinkage is the enemy of plastic mold processors, especially for large-scale home appliance precision plastic mold products with high surface quality requirements. Therefore, various technologies have been developed to minimize shrinkage and improve product quality. A simple solution is to modify the conventional core hole, but this method cannot be expected to be suitable for all resins. In addition, the gas-assisted method is also worth a try. Another method is to modify the mold. But moldmakers still have a lot of factors about mold design that can affect shrinkage. The geometry and material selection are usually determined by the raw material supplier and are not easily changed. This kind of defect severely limits the design and molding of precision plastic mold products for home appliances, especially large-scale thick-walled products such as the bevel case and display case of TV sets. Too short a filling phase will result in increased shrinkage and eventually more or larger shrinkage marks. After the part is filled, the excess material continues to fill the cavity to compensate for the shrinkage of the material

In order to improve the quality of the mold, the plastic mold company minimizes the complaints about the quality of the mold and handed it to the customer's satisfactory mold. Now it summarizes and summarizes the common problems of mold manufacturing, and establishes standards and implements according to requirements. This is very important, like friends. Can be collected! 1, the hot mouth slot must be rounded to avoid scratching the wire. 2, the mold guide post guide sleeve should be processed to the exhaust groove to prevent the guide post guide sleeve strain. 3, the mold must not have sharp corners, need chamfering treatment. Except where otherwise specified. 4. The inner mold and mold parts must not be welded without consent. 5. Important wearable parts such as row position, push block, shovel chicken, and pout must be nitrided and hardened. 6. The periphery of the mold product must be opened at the appropriate position.

For the specifications of the exhaust groove, please refer to the mold design manual. 7. Avoid using a sander to polish the mold as much as possible. If it is necessary to use a sander, you must use oil stone to save light (especially the parting surface). 8. The thimble adopts the hasco or dme standard, which is determined by the mold technical requirements determined by the bom table or other formal notices. 9, the mouth should be nitrided, you need to do a resale. The radius of the beak must meet the drawing requirements. The mouth is not nitrided and may have been injured before the mold. 10, the conventional structure mold must be arranged with the head, the two ends need to be smoothed, the small mold pre-pressure 0.1mm, the large mold pre-pressure 0.1mm-0.15mm. 11. The diameter of the positioning ring must conform to the drawings. The form and position of the top joint must conform to the drawings. 12, mold transfer acceptance: need to cooperate with the mold engineer according to the 'mold check table' acceptance before passing the package to mold. 13. Before the mold is transferred, the water pressure should be tested (100pa or more). After the water is accepted and accepted, the air gun should be used to blow the water clean. 14. According to the bom table or the confirmed pattern, the faucet must be machined and installed according to the die. Drill holes must not be drilled, and sharp angles must be chamfered. 15. All the words on the mold must be neat, correct, and not to be twisted. 16, the mold needs to be installed on the four sides of the side lock (straight body lock). If the side lock cannot be installed, you need to install a taper lock or a cone lock. The taper lock should be installed sideways. 17, all screws and mold parts need to be the preferred standard parts, the screw head can not be sawn off. The effective locking length of the screw must be sufficient, normally 1.5 or 2. 18. The surface treatment of the internal mold surface must be carried out in accordance with the bom table or other officially notified technical requirements. The processing lines on the non-adhesive surface (line cutting, milling machine, cnc trampoline, spark machine) should also be polished with oil stone. 19. For all internal mold materials, the mold blank level requirements must be purchased according to the order or the technical requirements officially confirmed during the design review process.

A proof of material must be provided, and if it is a hard mold, a heat treatment report must be provided. All relevant proofs. 20, the front and back inner molds of all molds, inserts, row position, slant top, straight top (push block), shovel chicken, etc. need to process a waist round pit on the bottom or side, the chair mould manufacturers material name and hardness are carved out. 21, thimble, cylinder, thimble, slant top and thimble board should be engraved with the corresponding identification code for easy installation. If the thimble position is not horizontal on the product, you need to make the ejector pin 'd' type or use the anti-rotation key to position. 22, the outer surface of the mold embryo in the manufacturing process, need to pay attention to maintenance, to prevent rust, scratches. Before the mold is packaged, the inner mold needs to be sprayed with white/colorless rust inhibitor. All mold surfaces must be cleaned and then buttered. 23, the position must have a position. Positioning methods include slingshot, wave bead, hasco (dme) standard position clip, etc., which need to be in accordance with the requirements of each project.

The row needs to have a bead and a wear plate. For the beading and wear-resistant plates, wear-resistant hard materials must be used, and oil grooves are required. 24. The row guide column must be pressed tightly and cannot be rotated or loosened. The tail of the inclined guide column must be processed into a hemispherical or truncated cone shape to help ensure normal movement of the row. If there are two or more inclined guide columns in the same row position, the length, size and inclination of the inclined guide columns must be the same. 25, the inclined top seat must use wear-resistant hard material. The inclined top must be machined with oil grooves. The inclined top seat is generally hardened with 2510 or cr12 to hrc40-45 degrees. Because the inclined top seat is subjected to the impact load, it cannot be too hard or it will break and chamfer the c angle at all right angles. . A sloping top guide (bronze) is required. Do not weld.