We are working on a 40" x 60" projection augmented landscape model. Due to COVID, we no longer have access to a large scale PLA printer, so we are considering our Formlabs 3 printer for the job. We will be printing 96 separate 127mm x 127mm interlocking landscape segments. After some initial tests, we are concerned about slight warping on straight edges of the prints. We are hoping forum members can provide us advice on best practices (resin type, preform layout, wash and cure protocol, etc) so that our prints can connect as seamlessly as possible.
Here are photographs from our recent tests. These models we printed with the following setting:
Clear Resin V4
Layer Thickness: 50 microns
Touch Point Size: .35
Form Wash and Cure
Here are the printed models
Here is a rendering of the entire model
Any advice would be greatly appreciated.
In general there’s always going to be a seam there, you can get really close to having edges line up perfectly with high precision injection molded pieces but 3D printing isn’t going to get nearly that close. In particular the side of the print that’s pointing downward or has supports on it will turn out with soft features and extra material around the supports.
It’s a result of how SLA printers work, there’s no way to prevent the laser spot from continuing through the printing layer and curing extra material on the opposite side of the print, so you’ll get a bit of extra curing on the bottom side.
The best way to avoid it is to make sure that any edges or details that need to be sharp should be mostly facing upward.
If that’s not possible, then you might need to explore other options. For what it looks like you’re making you may consider something like a CNC machine which can carve the relief pattern. Ultimately it can be the case of using the right tool for the job.
In my mind the best may to achieve the flush finished edges you are after is to add over-sized margin areas.
If you add a boarder to each tile with no detail that you can cut off, this will allow you to control the edges far better then can be achieved on the printer. Unfortunately this will mean the locating pins will have to be fitted as separate parts with only the pockets printed into the side of each tile.
If the tiles are printed vertically, then a extra border would only have to be added to the edge nearest the build platform. And the build would allow at least one extra tile.
there have been some major issues with the Form 3 compared to the Form 2. One of the things noticed is that dimensional accuracy is noticeably worse with Form 3 prints compared to the same print done on a Form 2.
Check out this thread here: Bad prints out of brand New Form 3
unfortunately I don’t foresee you having great success given the inherent problems this printer is currently having until Formlabs figure things out better.