How do I treat model dirt in moulds?

Wed Apr 26 22:08:44 CST 2023

Forming moulds, a number of different methods are used to improve mould fouling in elastomeric rubber compounding. These techniques include internal release of release agents, external release agent sprays, mould surface treatments and appropriate process parameters. A more effective approach is to use a combination of these methods.

It is important that all elastomer blends in the pattern have at least one internal release agent. These internal release aids are usually waxes, oleic acid, phosphoric acid or other low molecular weight compounds that move to the surface during the moulding process and form a protective film on the mould surface. Although effective, the addition of too many internal release agents can result in the build-up of fouling on the mould surface.

External release agent sprays work in a similar way to internal release agents, but they are sprayed directly onto the mould surface before the part is moulded. They can also have the undesirable effect of fouling the mould by over spraying. External release agent sprays can be semi-fixed, reducing the frequency of spraying and the potential for excessive build-up. Today, most are aqueous reagents with a silicone or fluorine base as the main component.Forming moulds

Mould surface treatments help to protect the treated material from abrasion during processing, provide anti-corrosion protection against chemical attack through a variety of chemicals and by-products in the process, provide a smooth, non-porous surface quality to the part and reduce mould fouling. Chrome-nickel plating has been used extensively. Teflon, silicon-carbide and industrial grade nickel-plated diamonds provide greater longevity.

Mould fouling: A common problem with elastomer hybrid moulds is mould fouling. Mould fouling is an inherent tendency for the compound to adhere to the mould surface during processing. To the extent that mould fouling occurs, it becomes a thin viscous film of mixed deposits left on the mould surface. Mould fouling not only leads to reduced productivity, but also increases scrap rates. Production is affected because parts have to be moved more carefully and moulds have to be cleaned in stages, resulting in lost production time. The increase in scrap is caused by the breakage of parts in the mould and by in-mould defects caused by mould disposal.

Height adjustment

1、As there are differences in the closing heights of CNC presses, the die is shipped in its shortest state in order to prevent accidents.

2、First loosen the locking screw of the striking head nut;

3、Turn the striking head nut for adjustment, measure the rough height with calipers and then fine tune it;

4, repeatedly adjust until the appropriate height, and finally tighten the locking screw until the locking nut can be tightened.