PLASTICS ENGINEERING COMPANY SHEBOYGAN, WISCONSIN 53082-0758 U.S.A.

3518 LAKESHORE ROAD POST OFFICE BOX 758 PHONE 920-458-2121 FAX 920-458-1923

Molding Method Guide

Plenco thermoset molding compounds can and are being successfully molded by cold powder compression, preheat compression, transfer and injection molding methods. However, in some instances, there can be problems associated with the processing of some compounds by a particular molding method. The following table summaries these problems by compound and molding method.

Compound	Cold Powder Compression	Preheat Compression	Transfer	Injection
Phenolic	See #1	See #3	See #3	None
Melamine-Phenolic	See #1	None	None	See #6
Granular Polyester	See #2	See #4	See #4	None
BMC	None	See #5	None	None

1. Plenco does not typically recommend cold powder compression molding of our phenolic and melamine-phenolic molding compounds for some applications, due to the potential problems associated with this molding method. The following list outlines them.
• The material does not fill out the cavity as well as a preheated charge.
• It is more difficult to consistently obtain a dense, well packed out part.
• It is more difficult to insure that the volatiles are removed before the part cures.
• It requires a longer cycle time to cure the part.
• Parts tend to have lower physical and electrical properties than those molded with a preheated charge.

2. Plenco does not typically recommend cold powder compression molding of our granular polyester molding compounds due to the poor surface appearance it generally produces with this material.
3. Some of Plenco's nodular or briquetted phenolic molding compounds do not preform very well. A screw preplasticizer is the preferred method of preheating these compounds for compression or transfer molding. Plenco can identify for you which compounds fall into this category.
4. Plenco does not typically recommend preforming our granular polyester molding compounds, since preheated preforms generally produce a poor surface appearance. A screw preplasticizer is the preferred method of preheating these compounds for compression or transfer molding.
5. Plenco BMC can be preheated but generally is not since the material molds well at low stock temperatures. When preheated, the form will always be a "log" of customer specified weight and diameter or a "slug" of bulk material. BMC is not generally preformed or screw preplasticized.
6. Plenco does not typically recommend injection molding our melamine-phenolic compounds since they exhibit the typical single stage resin problem of having a very narrow processing window.

This information is suggested as a guide to those interested in processing Plenco Thermoset molding materials. The information presented is for your evaluation and may or may not be compatible for all mold designs, runner systems, press configurations, and material rheology. Please feel free to call Plenco with any questions about PLENCO molding materials or processing and a Technical Service Representative will assist you.