Home Consumer Appliance plastic molds

• mold cavity:1
• Hotrunner:2 drops with “HOTSET”  heating coils,separted temperaturer controller
• mold cavity steel:DIN 1.2738
• mold core steel:DIN 1.2312
• mold slider insert:DIN 1.2738 with Nitriding,
• mold insert:Copper Beryllium for good cooling
• Plastic material:ABS
• Cycle time:25 Secs
• Delivery time:50 days.

Our Home Consumer Appliance plastic molds making service includes:

Home Consumer Appliance plastic mold surface imperfection repair tips:

SURFACE IMPERFECTIONS

Many minor imperfections may appear on the surface of a plastic mold. Occurrence of such imperfections, the repair of which may require only a sanding operation, immediately reduces the benefits inherent in plastic molding. Such imperfections, and their general causes include:

1. Rippled or uneven appearance— Pattern not splined or sanded sufficiently or properly.
2. Rough surface, with the appearance of wood grain, minor indentations, etc.— Pattern not polished sufficiently or surface improperly prepared. Or, parting film or agent has not been properly applied, dust or dirt was on the surface before application of gel coat or overlay.
3. Regular lines at periodic intervals— Station marks in the pattern not removed, or the pressure of braces causing raised areas in the mold.
4. Pattern transfer— Application of first plies of glass too soon after application of gel coat or overlay, or too thin gel coat or overlay.
5. Surface pitting— Mixing resin too rapidly or careless application of surface coat, or moisture in the plaster mold.

Repair Methods

The extent of surface repair depends on the requirements of the plastic mold. The alternatives are sanding and filling, or complete roughing up and refacing of the plastic mold surface. Soko recommends complete replacement if the surface contains more than 5 pits/sq inch. If such pitting exists in one area it probably exists throughout. Tapping the surface lightly with a ball peen hammer will show up such faulty areas. Surface Replacement. Where the entire surface or a substantial area of the plastic mold surface is to be replaced, the following procedure is usually satisfactory:

• 1. On a cast surface sand the faulty plastic mold face (No. 60 grit should be satisfactory ) to remove a fairly uniform layer. In laminated plastic molds, strip off one or two surface layers of cloth instead of sanding.
• 2. Prepare the mold surface against which the face is to be formed in the same manner conventional plaster or wood molds are prepared, i.e., dry, and apply parting compound.
• 3. Brush on surface coat of resin and dust with a nylon flocking. After surface coat gels blow off excess flock.
• 4. Apply one or two layers of glass fabric ( 150, 164 or equivalent ) with a suitable laminating resin to the surface coat resin. Dust with flock unless continuing immediately.
• 5. Liberally apply thixotropic laminating resin to both the roughened plastic mold face and to the laminated surface. If the plastic mold is a thin-walled laminate, perforate the body laminate with a pattern of 3/16-in. holes to allow for air bleed.
• 6. Mush the roughened plastic mold face into the new face by making contact first at one side of the plastic mold and then progressing slowly toward the other, forcing out air and excess resin.
• 7. Allow resin to cure, trim off excess resin and clean up plastic mold.

A repair as outlined above is expensive, but effective. Application of the surface laminate may be eliminated, but use of the laminate prevents subsequent breaking through the surface coat to any small air bubbles retained in the interface between the new surface and the body of the plastic mold.