Acrylic plattform upgrade for the Replicator
by Eureka, published
This is a very simple print, consisting of one distance for the Z-endstop, and four clamps to hold a 3 mm thick acrylic sheet onto your Replicator plattform, just like on the Replicator 2!
The benefit of PLA printing on an acrylic surface is that it bonds better to it, then to painters tape. This will reduce the risc of curling and warping considerably. Also, since the acrylic sheet ment to be used with this clamps is only 3 mm thick, after the print is done, you remove the sheet and gently bend it in different direction to loosen the print from the surface. That should make it easy to snap it off with your fingers.
Also, if you happen to run the extruders into the plattform, a acrylic sheet is much cheaper to replace then the aluminium platform.
Further more, since temperature and distance between nozzle and acrylic sheet matters, with this mod, you can actually get more control over how hard the part is bonded to the buildplate! That means for instance that you can print supported structures without a raft ( just reduce the space between the nozzle and buildplate alittle ) and the supportstructure still wont fall over.
Also, you cant control thoose really stubborn prints that never seem to stop curling. Just close the gap even further, and it will bond like nothing else.
Observe that an acrylic base is only good for PLA prints. If you print the four sheet clamps in PLA, these will melt if the plattform is hot, so change that "M109 S110" code in your program to "M109 S0". Since PLA rarely need any heated buildplate at all, this will probely not matter to anyone using PLA. Also, not all acrylic sheets are the same, so any acrylic sheet wont do. I have bought acrylic sheets that doesnt work at all, everything got welded to it permanently. Other acrylic sheets that works like they where magic! So you need to try different brands and sources. I currently use one called "Perspex" but i cant guarantee that all acrylic sheets called "Perspex" are the same, so it is up to you to find the source of acrylic that works for you.
In order to make room for the 3 mm acrylic sheet, you need to use the long piece and push it down on the wooden edge that makes contact with the Z-endstop when the machine goes to home axis. Look at the first picture and you will see the distance piece in place next to the Z-screw. Make sure it has a tight fit so they wont come loose by vibrations. You should also trim all surfaces on these printed parts, so the are without obstructions, smooth and wont catch on something. It is also a good idea to sand down the edges of the acrylic sheet alittle, to make it easier to push on the four clamps to hold it in place.
As for the position of the four clamps, you can put them anywhere they fit, but be careful not to put them in a place where the nozzles can collide with them, otherwise you might damage your machine. My recommendation is at positions 3 o'clock, 5 o'clock, 9 o'clock and 11 o'clock. If you find the nuts underneath the platform being in the way, just choose the closest place. This should probably work most of the time, but keep in mind, the location of these clamps depends on how the extruders will move during the print.
Finally, give the nozzle some extra room over the platform, extruding too close to the acrylic will fuse the PLA into the acryllic and it wont come out again. Like ever. Start at twice the distance you normally have, and the tighten carefully between each attempted print to find the sweet spot. And as always, make sure your platform surface is properly degreased!
When your unwarped, uncurled, beutiful print is done, just remove the acrylic sheet, bend it genlty in different directions until you hear cracking noises, and just snap off the print with your fingers.