Compression molded out of oven (MDF molds?)
I have been researching on this page for a couple of weeks now and each time I am closer to know what I want to do with the information of this community.
I will make a compression machine and I have seen some different ways to use the molds:
#1. The one Dave shows in his videos: heat the oven, put the plastic in the mold and use the press built into the machine.
#2. Another technique I have seen is to heat the plastic in the open mold, then take out the mold and use a press to mold the piece.
#3. And the other is to heat the plastic in a tray and pour the half melted plastic to a mold outside and exert pressure with a machine.
While the first 2 methods are made with metal molds, in the last I have seen a video (https://vimeo.com/josecamachopd/pplastic) where they make MDF molds.
I wanted to know, according to your experience, the pros and cons of these different types of finishes. I suppose that in the technique #3 the molds are more economical, and in addition, you can heat the plastic in a conventional oven (not the PP machine).
What can you tell me about these techniques, in terms of finished products and production times or something else.
Not sure. MDF is fabricated at temperatures comparable to the plastic temperature. I don’t know what is released at that point. If you look at section VI of a typical MSDS http://www.hardwoodweb.com/architectural/docs/MSDSUltraStock.pdf it talks about some of what can be released during thermal decomposition (without specifying a temperature). I would research it a bit before a lot of use.
As far as using it, I’ve used wood molds with my injection machine. I use aluminum tape on the contact surfaces to avoid sticking, and make sure all the thicknesses are robust enough to handle the pressure. For a limited number of runs it works well.
Heating MDF might indeed not be the healthiest way to go, at least not indoors, without ventilation and a mask, but the same goes for working with the plastics so the point could be made that if using MDF as a mould is not safe nor is melting the plastic!
Combining the techniques (MDF with tape/foil) also might improve both.
You must be logged in to reply to this topic.