Wednesday, March 18, 2015

More on Print Bonding - Use of FR-4

I have printed a lot of PLA onto glass with my Prusa I3 but for some reason I could not get good adhesion with the new printer.  In fairness I never tried hair spray which I had success with previously but I was out.   The reason that I was out was that I had used some ABS goop when I ran out and it worked fine.   Had been using it ever since.  No bonding problems what so ever on the Prusa I3.

Alas, not the case now.   I have some hair spray on order and will try it when it gets here for both PLA and ABS.   In the meantime I decided to experiment with a new material for my build platform.  I had read good things about FR-4 and so decided to buy some from eBay.  FR-4 is one of the materials used for circuit boards and is a very stiff, very rigid, fiberglass composite.    The one that I bought did not have copper on it though I understand that some people print on the copper side as well?

The sheet that I bought was 1.6mm thick and 8"x6" which is just about a perfect width for the Duplicator 4S though a little long.   Enter the Dremel.   This stuff is not easy to cut.   The first tool that I used just about burnt up.  I did get it cut using a little circular saw but not as nicely as I would have liked.  But it fits.  I made some little clips to fasten my glass build plate and had to modify them a little given that the FR-4 is thinner.

What you see in the pictures to the right is the FR-4 on the build platform with the platform being held by version one of my clips printed on my Prusa I3.   Version 2 of the clips, or the insert anyway, are what is being printed on the platform now.

The first couple prints that I did were right onto the Fr-4.   After the first couple I cleaned it with acetone and then added a little ABS goop.   It seemed to help with the bonding so that is my process now.

I also printed a little spatula as the last thing that I want to do is use a metal knife and scratch the FR-4.

Once things were dialed in it was pretty much like printing on glass.  Except that it is harder to see white PLA on yellowish FR-4!   A minor issue.  I will say, however, that what I had read about it being a good platform for bonding is true.   Here is a short video that illustrates both the bonding, and the release once the platform has cooled.
 

I love the way stuff sticks to the point of madness but when the FR-4 has cooled it just about slides off.

I have read that some folks have had FR-4 lose adhesion over time.  Obviously I will have to wait and see.     I find it hard to believe that a little steel wool, some very fine emery paper, and then some ABS goop will not remedy any stickage issues.

I will update as needed.  I also have to try ABS but as that is what most people have used with FR-4 I suspect it will be fine.

[UPDATE]

Printed some ABS and as expected it worked well.  If possible even better than the PLA!  I let the build plate completely cool and the part I printed, which had been firmly attached, was completely loose when I came back to it.

An interesting observation when printing ABS right after PLA.   The build platform seems to be higher?  As in the ABS is more smushed onto it?   Could it be that the higher heat has the FR4, and maybe even the build plate under it, to expand that much?   It makes sense that it would but I was not expecting as much of a variation.

I LOVE THIS STUFF!

I can not imagine printing on anything else at this point.  

2 comments:

  1. You need to use a tool made of Tungsten carbide to cut FR-4.

    ReplyDelete
  2. You need to use a tool made of Tungsten carbide to cut FR-4.

    ReplyDelete