What are the defects of wax mold in precision casting?

In the precision casting production process for various reasons, the wax mold made by the wax molding machine will produce some defects, today precision casting manufacturers Raymond Machinery for everyone to analyze the precision casting in the wax mold defects are.

1. The wax mold is not full, lack of flesh.

• Wax material temperature is low, cold wax
• Slow injection speed, low molding temperature, causing the wax to cool down quickly in the flow process.
• Cold residue on the injection nozzle
• Improper position of the injection port

It is shown in the corner and edge part or thin-walled part of the wax mold is not filled with enough, and there are rounded corners in the angular place, similar to the underpouring of the metal casting.

2. Bubble in wax mold.

• Wax flow rate is too high
• Improperly designed mold exhaust, wax contains water.
• Wax temperature is too high

One kind of bubbles is surface bubbles, i.e. subcutaneous bubbles visible with naked eyes, there are individual distribution, there are dense distribution; another kind of bubbles is deeper bubbles in the wax mold, usually concentrated larger bubbles, which can not be seen by naked eyes, but bulge from the local part of the wax mold, which appear in the center part of the wax mold and the last part of the cooled part, which is a result of the release of the internal pressure and the expansion of the gases.

3.Surface wrinkles

• Insufficient temperature of the wax material, low injection speed.
• Improper coordination between wax movement and molding temperature.
• Damaged or uncleaned inner surface of the mold, improper placement of the cooled metal block, etc.

Traces of movement on the surface of the wax mold, with deep lines, similar to cold segregation defects in metal castings; minor wrinkles can be removed by grinding. There is also around the core, around the holes, sometimes you can see the joints, slightly concave, in fact, the meeting of the two streams of wax is not well fused, this is the result of the wax temperature is not enough, the pressure is not enough.

4. Sinking and shrinking of wax mold

• High gas content of wax
• Insufficient injection pressure and time
• Higher temperature of the wax material and insufficient cooling time.

Too much mold release agent may cause the wax properties to deteriorate. Surface concavity involves a large area and is difficult to repair.

5. Wax mold deformation

• After the wax mold is taken out from the press, besides the size change, it is deformed because of the improper way of taking it out.
• The holding time of wax injection is too short.

The wax mold is still cooling and the temperature field changes and flexure deformation, so the wax mold just taken out from the press should be placed carefully, usually with a larger plane as the benchmark, and if necessary, use the shape of the deformed part, make a metal block embedded in the wax mold to prevent deformation, and also even if it is sufficiently cooled. It is also possible that the wax is too soft, the components of the press are not suitable etc.

6. Wax mold flying edge, hairy wing (Phi sewing)

• The mold is too dirty, the wear and tear causes the wax sheet to escape from the joints.
• The pressure of wax injection is too high
• The temperature of the mold is too high.

It is mainly due to the lack of precision of press molding, the damage of press molding parting surface or the jointing surface of the inner parts of the molding, or the attachment of unclean materials, or the insufficiency of molding force, or the high pressure of injection. Or the wax temperature is too high. The fins must be completely removed before the wax mold can be used.

7. Cracking of wax mold

• The holding time of wax injection is too long and the pressure is too high.
• Lack of pulling slope when taking the mold.

The above is the precision casting wax mold defects cause analysis. Precision casting manufacturers Raymond Machinery focusing on the production of precision casting, sand casting, from mold manufacturing to precision casting production to provide joint development and one-stop customized services, is committed to China’s high-end manufacturing industry to provide quality casting parts. If there is a related to precision casting needs, welcome to consult us.