Author - china plastic injection molding

Common quality problems of injection parts

A. Appearance:
Product surface often appears: shrinkage, drape, mixed color, mixed point, drag pattern, mold pattern, water pattern (material pattern), oil stain, crack, water pattern, air pattern, flow pattern, water pattern, deformation, color difference, uneven color, scratch, top white, top height, top piercing, blind hole, broken column, bubble, fogging, brittle, air pattern, uneven erosion pattern, unclear word mark, lack of glue, nozzle damage, residual glue deviation Long wait
 
B. In terms of structure:
1. Screw column position: lack of glue, flapping edge, […]

How to choose the best gate location

1. The gate must be designed in the area with the largest wall thickness.
2. The gate should not be set near the high stress area.
3. For the long parts, especially for the reinforced mixture, if the motor is possible, the gate should be set along the longitudinal direction rather than the transverse direction or in the center.
4. If there are two or more cavities, the parts and gate should be symmetrically arranged along the sprue.
5. For axially symmetrical parts, […]

Defect analysis and elimination of black specks

What is black specks?
Black specks are dark or dark streaks on the surface of products, and black streamline appears along the flow direction near the gate, which is a surface quality problem, as shown in the figure
Black spot and black stripe
Defect analysis and elimination of black specks
1) The melt temperature is too high
If the material temperature is too high, the melt will overheat and decompose, forming carbides. In order to avoid the overheat decomposition of the melt, the temperature […]

Analysis and elimination of sink mark defects

What is sink mark?
Dent and sink mark are caused by local shrinkage caused by gate sealing or lack of material injection.
The depression or micro depression on the surface of injection molded products is an old problem in the process of injection molding. Dents are generally caused by the increase of the shrinkage rate of plastic products caused by the increase of the wall thickness. They may appear near the external sharp corner or the sudden change of the wall […]

How to solve the problem of insufficient filling in the process of plastic injection molding

In the process of plastic injection molding, there will be a variety of problems, and insufficient filling is a phenomenon with high probability, so what is the reason for insufficient filling? How should we solve this problem? Mr. Fu, a teacher of Jiangsu injection molding factory for many years, shared it with you.
Plastic injection processing
1、 The main reasons for insufficient filling in plastic injection molding are as follows:
1. Insufficient resin capacity.
2. There was insufficient pressure in the cavity.
3. The […]

Analysis of cooling time in injection molding

The cooling time of plastic injection molding products accounts for about 80% of the whole injection molding production cycle. If the injection molding parts are cooled properly, the product quality is qualified. If the cooling is not qualified, it will lead to warpage deformation or surface defects, which will affect the dimensional stability of the products. The injection molding manufacturers analyze the cooling of injection molding parts for you.
 
The cooling time of injection molded parts generally refers to the […]

Causes and solutions of bubbles in injection molding

In the process of injection molding, bubble is a very common phenomenon, light is harmless, heavy directly affects the actual quality of injection molding products.
 
1、 Causes of bubbles in injection molding
In the process of injection molding, when the wall thickness of the product is large, the cooling speed of the outer surface is faster than that of the central part. Therefore, with the cooling process, the resin in the central part shrinks and expands to the surface, resulting in […]

How to solve the peculiar smell of injection molding products

Injection molding products are not only required to be qualified in quality, but also have adverse effects on customers if there is a peculiar smell in the produced injection parts. In particular, some injection molding plants use qualified plastic particles, and the increase of peculiar smell will directly affect consumers’ purchase of products. Therefore, injection molding products need to be guaranteed that there is no bad smell.
 
1. Strictly control the use of additives
The TERT amines used in the production […]

Three factors of poor gloss of injection molded parts

Many injection molding factories will encounter similar problems. There is no problem with the product quality, but the glossiness of the product is not up to standard, which eventually leads to the rejection of the injection molded parts. In addition to the problems of the plastic itself, there are also problems such as injection mold, production, design, etc
 
1. In the injection molding production process
There are several options to try, which can be changed by adjusting mold temperature, feed / […]

Three main reasons for dimensional changes of injection molded parts during processing

No matter what kind of plastic is, it has a certain shrinkage rate. If it is not controlled properly, it will directly lead to the change of the size of the injection molded parts. If the change is too large, it will directly lead to the unqualified quality of the injection molding products. This is a period that many injection molding factories do not want to see, and the three major factors affecting the dimensional change of injection molding […]