Re: Replicator 2 - raft impossible to remove

[Alex Lau]

I have the same problem, not sure what tools to use to remove overzealous supports/rafts..

On Thursday, January 3, 2013 12:53:50 PM UTC-5, Eric Cheung wrote:

Hi, I finally got my Rep2 yesterday, so no extensive testing yet.

I was test-printing a round plate using Makerware default everything including medium quality, with default PLA. I tested with using a raft. The raft was printed under the shadow of the part, with some difficulty with sticking, but the rest of the part printed normally over it. The part w/ raft came off the blue-taped build plate easily, but the raft won't come off my round plate nearly as easily. In fact, it stuck so well, I can't even grind it off using a coarse grid sand paper. Now the bottom of the plate is rougher than concrete pavement.

Any ideas? Would printing with support be as difficult as this? Thanks!

[Darrell jan]

Depending on your model, you might not need the raft. 

Personally, I find that ABS support is easier to remove than PLA support. But depending on your model, it can be a pain either way. Several times, I've broken off some of the fine features in my model while removing the support.  I suppose with practice and care it can always be done, eventually. But I've ordered soluble PVC to give that a try (I have a dual extruder Replicator).

Darrell

[KOS]

Hey guys, don't fret over the raft! It seems to be one of the scariest things new Replicator 2 owners (including myself at the beginning) have troubles with - that said, there are things you can do to make it easier on you!

My first recommendation is to stop using Makerware and switch to the RepG software, it's such a big difference I can't even start to explain why it's so much better - but it is!

In the RepG software you can define the raft layer thickness, density, how many actual layers the raft is etc, try tweaking those settings (just google repG wiki for more info on basic settings).

Another thing you can do is lower your print temp! Try printing around 200-205c.

As for tools, I've found the best tool for removing support material / raft leftovers is a simple clays sculpting scraper (http://www.nmclay.com/mmNMCLAY/Images/tool/KTLT6-8.jpg). It almost has a blade-like edge that you can just rub back and forth on the surface and it takes it all right off - then just finish with a sanding.

Give the above a shot!

-KOS

[Eric Cheung]

Thanks! The advice by KOS are pretty good start. The limited options in MW could really corner you with the raft problem. RepG, which I've been playing with over the weekend, offers many more adjustments that makes huge differences. I'm learning them and putting them onto a google doc over time. I do, however, have a preference for simple, standardized solutions, over non-standard methods that requires purchases of new tools, plate, or hair sprays.

First:

I found that the raft is needed most of the time. If your part has any resemblance of a large base, it is highly likely that it will warp and peel off the build plate after about 3-5mm of z-height. This is simply because of the thermal contraction and poor adhesion to the build plate. Without going out of the way to get new build plate surfaces (lack of standard approach), rafting is the first option.

MW probable cause:

Inline with KOS's, I think MW prints the raft as a two layer grill, at the same temperature and speed as the rest of the build. Also no wait time between rafting and printing the part. The result is some insanely good bond between the raft and the part base. Added, if you have a large area flat base, which is what I had, the raft will become part of the final object.

RepG:

As KOS mentioned, you can control parameters in RepG like lower temperatures, to make the bond weaker.

Also, by default, the geometry of the raft in RepG is different (and printed slowly)! It prints parallel lines in the y-direction (front to back of the bot), and then TWO or so layers of parallel lines in the x-direction (left to right of the bot). This makes the raft easier to peel off, just like spaghetti strands. This would also play into how you orient your model for print. If your part has an obvious length axis, it would definitely be easier to peel the spaghetti off if it is printed perpendicular to the length, rather than parallel. 

In addition:

When I was playing with Nylon, which even greater warping than PLA, the default rafting could peel off the build plate with the part! The easy fix that i'm using so far is to make a super-sized raft (option in RepG). Huge raft holds onto build plate better and fights against the warping forces from the part.

Thanks!!