Large Scale Central

3D printing and Sketchup

Modeling Technical Modeling
#1

If I draw it in Sketchup what needs to be done if anything to get a file that then can be used on a 3D printer.

And for that matter a CNC lathe or mill, or CNC router? Do all of these devices use the same file formats and does sketchup give you the right file types? mainly interested in the 3D printing aspect now that I have access to at least one and maybe others.

What do I need to know about designing a piece so that it can be printed, such as orientation, undercuts, etc?

Basically i would like a basic down and dirty, if possible, on how to take what I dream up in Sketchup and turn that into a real part.

#2

most of my work with CNC mills and routers use 2d rather than 3d drawings the router cuts a shape based on the drawing to a certain depth several layers of cut are possible. true 3d cutting is of course possible such as carving a boat hull from a block of wood, again the actual cutting tends to be a series of layers. this type of milling gets files much like those for 3d printing.

I design kayak kits. the plywood is cut on a CNC router. the shapes are complicated but flat. these are some I did in a class several years ago.

#3

Devon Sinsley said:

If I draw it in Sketchup what needs to be done if anything to get a file that then can be used on a 3D printer.

Basically i would like a basic down and dirty, if possible, on how to take what I dream up in Sketchup and turn that into a real part.

Devon - the short answer is that SketchUp allows you to export STL files (you need to add a plug-in to do that but it is free) - most, if not all, 3D printers will accept STL format.

For a longer answer you may want to view the presentation that I did on 3D printers at the ECLSTS a few years ago. It is here:

https://www.youtube.com/watch?v=uR_z6YByr2U

The video speaks to your other questions.

dave

#4

For 3D printing, I’ve only done things with modeling programs like blender3d. I export obj files from that into Netfabb Free, use that to ‘clean’ up the holes and errors and then export STL files that I upload to Shapeways.

For my X90 3D router, I do flat shapes using Inkscape, save them as DXF, then import that into CamBam. In CamBam I can select the different layers I made in Inkscape and assign different depths of cut to those. I generally only use one bit, a 1/32 endmill and make multiple passes to cut out styrene sheet for my buildings. I guess it’s sort of a ‘poor mans’ laser cutter if you will.

I’m not a real fan of Sketchup. I’ve played with it a bit but I spent many years doing 3D game characters so I gravitate toward 3D model types of software. Blender is free and very powerful. Sorry I can’t be of more specific help.

#5

Thanks David,

Great video. For others you will need his PowerPoint to make sense of it. Hard to see the screen

#6

My CNC mill uses G-code whereas when I do laser cutting, I use dxf files generated directly by DesignSpark Mechanical. DesignSpark also does 3D stl files and will even allow for things like “shell thickness” and “void spaces.”

For a while I was converting the DesignSpark drawings to svg using Inkscape, but this would continually introduce errors, both in scaling and placement of objects. For example, a circle inside a rectangle may manifest itself outside of the rectangle after conversion though Inkscape.

I subsequently found that CorelDraw, that runs the laser, easily converted the DesignSpark dxf files, without error.

#7

I print a fair amount of stuff through Shapeways, using Sketchup, and .stl and .obj files have always gotten me where I wanted to go. I am currently looking into having an object cut on CNC, and most vendors want a .step file (or similar). Sketchup can’t do that, but I found a program called FreeCAD that can - which I am in the process of learning.

#8

Hey Devon, like others have stated my CNC Router mainly cuts in 2D for cutting out flat parts in different thickness’ of wood, plastic, or styrene. My design software is Vectric Pro and takes several different drawing files. The software allows me to specify all the parameters needed to cut out the parts, but it’s the G code that actually runs my machine.

However I can cut 3D carvings on my machine as long as I have a file, but they’re a one sided carving not a 3D part.

#9

Thanks guys that explains a lot.

#10

For three years I have been using Sketchup to design soundboxes for MyLocoSound speakers and to make building components for my railroad. As a result I would strongly recommend that you don’t send STL files from Sketchup direct to a 3D printer. Your STL files could well contain errors which you are not aware of; tiny gaps, misalignments, etc. I suggest that you download Netfabb (its free) which will verify and, if necessary, repair your STL files. The result will be a better quality print.

Regards

Peter Lucas

MyLocoSound

#11

Peter - thanks for the tip on Netfabb - I downloaded it and found that the 2017 version only has a 30 day preview - seems that Auto Desk bought it and no longer offers the basic version.

Fortunately I found a link that still has the version that is really free -

http://en.freedownloadmanager.org/Windows-PC/netfabb-Studio-Basic.html

I tried it on a few files and it does a nice job of fixing holes and other issues that come up - I had been using a plug-in for SketchUp but this may be better.

thanks again!

dave

#12

Another question I have after watching Dave’s video is on orientation and making sure I don’t end up with a but of stuff I don’t want. What are some basic guidelines for how to design and orient parts to strategically place supports?

#13

Devon - do your best to design and orient so that support material is not needed as it eats up filament & print time increases to say nothing of the difficulty you can run into removing it.

You can also split an item into two parts so that no support is needed - that was done on the deer I printed recently - no supports at all! All I had to do was glue the two pieces together.

dave

#14

OK Dave,

That picture answers quite a bit. he materiel then is pretty self supporting. I mean you have a lot of overhangs and undercuts on that. Seeing that I think I have a pretty good idea on what may or may not happen. At least enough to start experimenting.

#15

Devon - things that are at more than a 45 degree angle from vertical generally need supports - the only thing on the deer that might need support material is the snout. I printed it with supports turned off and got a pretty good result

dave

#16

Can there be any horizontal stuff that is unsupported? Can you print say something with a 2-3mm overhang?

#17

There will likely be hanging strands of filament but I have done it - better to add support material or change the design. A very small overhang works better than a long one.

dave

#18

Thanks Dave