Resin 3D printers - wagon plates
Posted: Thu Dec 03, 2020 4:32 pm
This all started a few months ago with a discussion between Steve and I about the fine print capability of fdm printers and the fact that resin printers are capable of much finer detail. To cut a long story short, after seeing some of Steve's work, I ended up splashing out on a resin printer - the Anycubic Photon S.
Although the drawing work is exactly the same and needs to generate an stl file, after that it's a very different beastie. The drawing still needs slicing but not with Cura, et al, it needs either dedicated software as supplied with the machine or the Cura resin printer equivalent, which is called "Chitubox".
The print volume of my printer is relatively limited so wagon sides would be a challenge and the process is also very slow, because of the layer heights of only 0.05mm, so it is more suited to small detailed components.
For various reasons the machine sat unboxed but not even switched on for a couple of months, but then something cropped up which gave me the incentive to bite the bullet and find how to actually use it!
You may have seen the FR tipper wagon I was playing with on https://gardenrails.org/forum/viewtopic ... &start=150 .
The photo of the prototype has a rather prominent cast wagon plate in the middle of the tipper side. I tried to print this using my ordinary printer but it really didn't want to know about the fine lettering around the edges, all I got was one or two odd blobs, so this was the ideal test project for my new machine.
Firstly I tried the test print file that came with the printer and was truly amazed at the quality and complexity of the print. This is it, and this prints as one piece with all the internal detail included:
Anyway, after refining my basic Sketchup drawing, having noticed a couple of errors, I put it through the slicer.
For technical reasons the print is produced upside down hanging from the build plate, and removal is easiest if the model hangs from supports, also it is said that it works best if the model is not parallel to the build plate. So I angled my wagon plate in the slicer and pressed on with it. An hour or so later there it was, hanging upside down on the bottom of the plate. It then needs washing in IPA to remove excess resin and then half an hour under a UV lamp to finish the resin curing.
I must say I was amazed at the quality, better than I had dared to even hope. The biggest problem was painting it, bearing in mind that the letters are only 0.2mm high!
I first sprayed it matt black with a very short, distant burst to avoid flooding it.
Then used white acrylic in various ways to pick out the lettering. The final version was simply using a 00000 brush under a magnifying glass. Not very good but it does look a bit like worn paintwork from a distance.
So I enlarged the lettering slightly, making it now a whole 0.4mm high! and changed the central numbering to give 3 different options. The plates themselves are 12mm wide.
I had also noticed that because the plate was angled in the printer, as all the gurus say should be done, there were microscopic steps across the face of the plate, so when I sliced the revised drawing I did it with the plates parallel to the build plate. An hour or so later I had 3 plates hanging from the build plate. One advantage of this type of printer is that it doesn't matter how many objects you print at once, it takes as long as the biggest one would take by itself.
Since these plates were intended for wagons that Andrew is planning, I put them in the post to him to finish and paint.
He chose to reverse my painting sequence by spraying white and infilling with black acrylic and wiping it off the faces of the lettering. This seems to have worked very well. It is possible to get coloured resins which would potentially ease this but I've only got the trial bottle of translucent green that came with the machine. It is also worth noting that the resin supplied seems to be somewhat brittle, but I don't know if others are less so.
As with anything, it's horses for courses, of course, but resin printers are amazing!
Although the drawing work is exactly the same and needs to generate an stl file, after that it's a very different beastie. The drawing still needs slicing but not with Cura, et al, it needs either dedicated software as supplied with the machine or the Cura resin printer equivalent, which is called "Chitubox".
The print volume of my printer is relatively limited so wagon sides would be a challenge and the process is also very slow, because of the layer heights of only 0.05mm, so it is more suited to small detailed components.
For various reasons the machine sat unboxed but not even switched on for a couple of months, but then something cropped up which gave me the incentive to bite the bullet and find how to actually use it!
You may have seen the FR tipper wagon I was playing with on https://gardenrails.org/forum/viewtopic ... &start=150 .
The photo of the prototype has a rather prominent cast wagon plate in the middle of the tipper side. I tried to print this using my ordinary printer but it really didn't want to know about the fine lettering around the edges, all I got was one or two odd blobs, so this was the ideal test project for my new machine.
Firstly I tried the test print file that came with the printer and was truly amazed at the quality and complexity of the print. This is it, and this prints as one piece with all the internal detail included:
Anyway, after refining my basic Sketchup drawing, having noticed a couple of errors, I put it through the slicer.
For technical reasons the print is produced upside down hanging from the build plate, and removal is easiest if the model hangs from supports, also it is said that it works best if the model is not parallel to the build plate. So I angled my wagon plate in the slicer and pressed on with it. An hour or so later there it was, hanging upside down on the bottom of the plate. It then needs washing in IPA to remove excess resin and then half an hour under a UV lamp to finish the resin curing.
I must say I was amazed at the quality, better than I had dared to even hope. The biggest problem was painting it, bearing in mind that the letters are only 0.2mm high!
I first sprayed it matt black with a very short, distant burst to avoid flooding it.
Then used white acrylic in various ways to pick out the lettering. The final version was simply using a 00000 brush under a magnifying glass. Not very good but it does look a bit like worn paintwork from a distance.
So I enlarged the lettering slightly, making it now a whole 0.4mm high! and changed the central numbering to give 3 different options. The plates themselves are 12mm wide.
I had also noticed that because the plate was angled in the printer, as all the gurus say should be done, there were microscopic steps across the face of the plate, so when I sliced the revised drawing I did it with the plates parallel to the build plate. An hour or so later I had 3 plates hanging from the build plate. One advantage of this type of printer is that it doesn't matter how many objects you print at once, it takes as long as the biggest one would take by itself.
Since these plates were intended for wagons that Andrew is planning, I put them in the post to him to finish and paint.
He chose to reverse my painting sequence by spraying white and infilling with black acrylic and wiping it off the faces of the lettering. This seems to have worked very well. It is possible to get coloured resins which would potentially ease this but I've only got the trial bottle of translucent green that came with the machine. It is also worth noting that the resin supplied seems to be somewhat brittle, but I don't know if others are less so.
As with anything, it's horses for courses, of course, but resin printers are amazing!