hot oil MTC

[Josue]

We receive a old mold,, this run a PC/ABS resin,, the previus company ran the mold using a HOT oil MTC
they say the temp ran at 90C,,but here we only use a water,, so I make samples using water at 90C

the original finsh of the parts as a texture,,, but the parts I got at first test was too shine,, so I increase the MTC temp to 100 and 110C,,, (matsui has a capacity to 120C),, so I got parts less bright, almost same as originals,, my question is , what is the "effect" between use a hot oil MTC and water MTC , becasue i think the oil should be use a higher temps,,,

resumen: I still fill that the parts need to be improve, I woul like to eliminate this bright totaly, sofar the way that i get closer was increasing the mold temp,, can you recommnend another processing issue?

im using this temps

260-255-255-250 Celcius, i already try higher temps,,,

thank you

[pjhall]

That might be a good experiment to try. Run with water Mold Temperature Controller and take cavity and core temp readings with a surface pyrometer and then do it again with oil (not sure if you have an oil MTC). I use oil MTC for mold temps over 220.

Changes in part thickness under the texture will show through the texture. A rib will sometimes show as darker line and if the part gets thinner the texture will show as shiny. For the shiny spot due to thinner part, over packing it will make the shiny section more shiny.

For textured Cosmetic parts it is best to have no changes in mold thickness. Not sure if this helps.

[rickbatey]

There are several factors that influence gloss level. At another plant we ran molded in color interior part, NO painting. The molds had a special low gloss grain. To completely mimic the tool surface, we had to run much hotter than usual and pack the parts very hard in the mold. Your grain may work that way as well. But it may have to do with the actual steel temp due to the oil transferring more heat to the mold steel. Interesting to perform DOE and test.
You might could get a company to blast the mold surface and drop the gloss so you can run with the water MTC. A company that specializes in grain and texturing should be able to help you.
Rick.

[brentb]

We use oil for products mentioned, sometimes for finish and sometimes for properties

In the clean room we use a SINGLE "thermolater, a special high temperature water unit.

Keep on molding!

brent

[Suhas]

I have also seen an IR unit that come down like a sprue picker, heat the mold surfaces before the mold closes. That heat helps with the texture. However in your case I am sure it is 'If the previous molder can run it, why cant you?' - So all the above are good suggestions. I think packing it more and hotter mold temps will help. Believe it or not, venting also plays a huge role. If the air does not get out, it gets trapped in the texture and the parts don't have the texture.
Regards,
Suhas

[Josue]

good point,,, I will make samples next week, and try some advices,, i get some ideas to try some thing diferent

thks