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Anonymous users2024-02-061. Insufficient plastic parts: mainly due to insufficient material supply, poor flow of melt filling, excessive inflation and poor exhaust, etc., resulting in dissatisfied filling cavities, incomplete plastic parts appearance or incomplete individual cavity filling.
2. Dimensional instability: mainly due to poor mold strength, poor precision, unstable working of the injection machine and unstable forming conditions, etc., the size of the plastic parts is unstable.
3. Air bubbles: due to excessive inflation or poor exhaust in the melt, the residual gas in the plastic parts is small in volume or in a series (note that it should be distinguished from vacuum bubbles).
4. Collapse pit (dent) or vacuum bubble: due to poor pressure holding and feeding, uneven cooling of plastic parts, uneven wall thickness and large plastic shrinkage.
5. The flash is too large: due to poor mold clamping, the gap is too large, the plastic fluidity is too good, and the plastic parts are extruded along the edge with too much material.
6. Poor welding: due to the low temperature of the material when the melt is diverted and converging, the resin and the admixture are not miscible and other reasons, the melt is poorly welded when it is converging, and obvious fine seams are produced along the surface or inside the plastic parts.
7. Corrugation on the surface of the plastic part: because the melt material does not flow neatly along the surface of the mold, fills the cavity, but flows in a semi-cured fluctuation shape on the cavity surface or the melt material has a stagnant phenomenon.
8. Poor demoulding: due to the over-filling effect, poor demoulding performance of the mold, etc., it is difficult to demould the plastic parts or the plastic parts are deformed and cracked after demoulding, or the residual direction of the plastic parts does not meet the design requirements.
9. Mica flake layered peeling: due to the mixing of foreign materials or low mold temperature, the shear effect of the melted material is too large when it flows along the surface of the mold, which makes the material peel off in a thin layer and the physical properties are reduced.
10. Gate sticking mold: due to the mechanical resistance in the gate sleeve, the cooling is not enough or the pulling rod fails, so that the gate sticks to the gate sleeve.
11. Poor transparency: due to the poor contact between the melt material and the surface of the mold, there are small holes on the surface of the plastic parts, which cause the light to radiate randomly or the plastic to decompose, there are foreign body impurities, or the surface of the mold is not bright, so that the transparency of the transparent plastic is poor or uneven.
12. Silver wire markings: due to the presence of moisture or inflation in the material, and too much volatiles, the melt material is subjected to excessive shearing action, and the melt material is poorly sealed with the surface of the mold, or it is rapidly cooled or mixed with foreign materials or decomposed and deteriorated, so that the surface of the plastic part appears along the direction of the material flow with silver-white luster needle-like stripes or mica flake markings.
13. Warpage and deformation: internal stress caused by residual stress, shear stress, cooling stress and uneven shrinkage during forming; Poor demoulding, insufficient cooling, insufficient strength of plastic parts, mold deformation and other reasons, so that the shape of plastic parts distortion, uneven warping or shape hole deviation, uneven wall thickness and other phenomena.
14. Cracks: Due to excessive internal stress of plastic parts, poor demoulding or rolling, uneven cooling, poor plastic performance or poor design of plastic parts and other drawbacks (such as deformation), fine cracks occur on the surface of plastic parts and near the feed port, or cracking or cracking does not occur under load and solvent action.
15. Black dots and black bars: due to the decomposition of plastics or flammable volatiles in the material, air and other decomposition and combustion under high temperature and high pressure, the combustible matter is injected into the plastic cavity with the melting, and black spots and black streaks appear on the surface of the plastic parts, or charcoal-like burns along the surface of the plastic parts.
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Anonymous users2024-02-05Generally, the clamping pressure does not need to be adjusted on the injection molding machine, but the stroke is adjusted. Mold tryout is a complex process, now try to describe:
1。On the mold, select the appropriate injection molding machine according to the overall size of the mold and the size of the product. (There are instructions in the design of the mold) in accordance with the principle of small first and then large, can choose small tonnage does not choose large tonnage.
2。The mold runs dry, and the mold is opened and closed, including the ejection action. Detailed documentation of the phenomena in the process.
3。Adjust the clamping thickness (not for direct pressure type).
4。Test the waters, (if necessary).
5。Parameter adjustment, pressure speed setting from low to high gradually increase, generally speaking, according to the experience of the initial set of the pressure speed can meet a injection volume full of the flow channel and enter the mold cavity 1 10 or so, mainly to observe whether the flow channel design is balanced, whether the glue port meets the design requirements. The second adjustment is to just fill the cavity.
After the third time, adjust the parameters to adjust the size and appearance.
The above process should be documented in detail. As a basis for modification of the mold.
After the mold test is completed, the mold cavity needs to be cleaned according to the requirements to prevent rust; Carry out actions such as blowing dry and rust prevention for water transportation. If there is a hot runner, the heating and temperature control of the hot runner need to be measured in detail separately. The runner plate is generally selected at 4-5 points, and the hot nozzle is directly selected at one point.
That's pretty much all I know.
The principle of in-mold injection molding is to put the printed decorative sheet into the injection mold, and then the gum. >>>More
Molding shrinkage is the percentage of the reduced value of the room temperature size to the original uncooled size after the plastic part is taken out of the mold and cooled to room temperature. Since shrinkage is not only the thermal expansion and cold contraction of the resin itself, but also related to various molding factors, the shrinkage rate of the plastic part after molding should be called the molding shrinkage.
As far as I know, the market for this product is relatively small, the automated factory purchases are generally German and Japanese machines, a more than 1 million, the protection function may be better than yours, if it is a general machine to buy a more than 100,000, spend 40,000 or 50,000 protectors should not be cost-effective, it is recommended that you seek injection molding machine manufacturers, to see if the machine can be equipped when the machine leaves the factory, ** of course it is too expensive, you should seek how to reduce costs, there will be a larger market.