Common problems in the production of PU wood-like products include:

1. Skin bubbles: the current production conditions must exist, only the number of problems.

2. Skin white line: the problem in current production conditions is how to reduce the white line and repair the place where the white line appears.

3. Skin hardness: according to the customer's requirements, there is no exact standard at present.

The above problems are analyzed as follows:

1. Skin bubbles: the causes are different according to the location and phenomenon. Typical reasons include:

(1) problems of foam gun:

A. During the mixing process: minimize the bubbles generated when the foaming material flows out from the nozzle, such as poor mixing and nozzle leakage.

B. Mixed speed (for low-voltage machine) : the higher the speed, the better; the smaller the flow rate, the better.

C. do not splash the tail material on the product.

D. High feed temperature, fast reaction, bubble will be reduced (mainly refers to winter).

E. The proportion of black material is high, air bubbles increase, and the pressure of the storage cylinder remains stable.

F. The head of the foam gun is mixed with dirt.

(2) influence of mold:

A. The mold temperature is high, and air bubbles will be reduced.

B. Mold exhaust effect, reasonable tilt Angle.

C. Mold structure determines some products more and some products less.

D. Smoothness of mold surface and cleanliness of mold surface.

(3) process control:

A. Effect of brush material and no brush, more injection material, less air bubble.

B. Late mold closing will reduce air bubbles.

C. Injection method and distribution of raw materials in the mold.

(4) effects of release agent:

A. Silicone oil release agent more bubbles, less wax bubbles.

2. Product skin white line problem:

When the raw material is injected into the mold, there will be a time difference, so that there will be a time difference when the raw material starts to react, and white lines will be generated when the interface overlaps before and after the reaction.

The main reasons are as follows:

Mold problems:

A. The mold temperature is 40-50 ℃, and the white line will be reduced.

B. The position of the white line is also different with the tilt Angle of the mold.

C. Local temperature of mold temperature is too high, resulting in different reaction time of raw materials and white lines.

D. If the product is too large or too thick, the white line will increase.

E. The water stain and mold release agent are not dry, resulting in white lines.

The foam gun:

A. High material temperature will reduce the white line, while high proportion of black material will make the white line hard.

B. (low pressure machine) high speed of gun head, good mixing effect, white line will be reduced.

C. White lines will be generated at the material head and end.

Process control:

A. The white line will be decreased with the increase of raw material perfusion.

B. After injection, the brush will reduce the white line.

3. Product hardness:

A. The density of raw materials is high, the hardness of products is increased, but the perfusion amount is increased.

B. high proportion of black material. Skin hardness increased.

C. High mold temperature and material temperature will reduce product hardness.

D. Mold release agent will reduce the hardness of the skin, while in-mold paint will increase the hardness of the skin.

Qualified products are required from the equipment, raw materials, process, mold and other aspects of control, so it is recommended to seek in the production processPolyurethane equipmentIntegrated supplier cooperation.