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Forum topic by Logan Windram posted 03-20-2016 02:33 PM 759 views 0 times favorited 11 replies Add to Favorites Watch
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Logan Windram

303 posts in 1921 days


03-20-2016 02:33 PM

I am taking a cabinet class that requires at least some portion of the project be cut on the schools CNC, so I have done the whole cabinet carcass and interior in sketch up.

My question is do I have to use a 8×4 sheet for the machine, or will it cut parts from 4×4 sheets as well? The cost is less for the 8×4 sheet of veneered ply, but transporting it in my SUV is not easy task. I have laid the parts out and they do not need a length more than 38 inches, so I can fit them into 2 4×4 sheets pretty easy. Also, is there anything you have to do with a sketch up file to prepare it for a run, other than attach and send it to the instructor ruining the machine?

I assume the machine can be set for stock of also any size, but want to be sure. I’d live to have my jigs and templates cut on the machine as well, so working on that currently. Pretty sweet stuff, will save me a ton of time and BS…

Thanks, LW


11 replies so far

View Ger21's profile

Ger21

1047 posts in 2590 days


#1 posted 03-20-2016 02:59 PM

The 4×4 shouldn’t be a problem.
As far as the other questions, it’s impossible to answer without knowing exactly what software the instructor is using, as well as his knowledge of using it. He’s really the only one that can tell you.
I’m not a fan of using Sketchup for CNC work, and have never done so.

-- Gerry, http://www.thecncwoodworker.com/index.html http://www.jointcam.com

View MadMark's profile

MadMark

976 posts in 912 days


#2 posted 03-20-2016 04:20 PM

Pretty much all CNC’s start at 0,0,0 and work out. The CNC itself has no idea where the material ends. 4×8 is the max, anything smaller will work.

M

-- Madmark - Madmark2150@yahoo.com Wiretreefarm.com

View Logan Windram's profile

Logan Windram

303 posts in 1921 days


#3 posted 03-20-2016 04:34 PM

That’s really helpful gents, confirming what I thought.

@ ger21- when I asked if a Sketchup file would help, he said that would be great- I believe he said he would have to convert it to g-code, I assume that is a CNC language that converts Sketchup language to a useable CNC file… He also said he could take shop drawing, pencil, and convert them to g-code as well, for students that never have used a 3D modeling tool.

@ mad mark- thank you- how exactly is the material held down while it cuts? I am going to try and have the CNC cut my patterned legs and stretchers, so cutting out of 8/4 4×6 pieces of white oak. Does the cutter make clean cuts even in open granted wood like oak?

Also, if you guys don’t use Sketchup, which I don’t really care for, what do you prefer? I am thinking about learning Rhino, is that a good program to convert to CNC cutting? I know we are going to learn a lot of this in class, but I’m trying to be the first one ready to go since a lot of the students I think will be really struggling to get their projects organized and planned and there will be a glut of people clogging up the shop shortly. I don’t get my personal shop back until August, so this is my only choice until then… It hurts!

View bonesbr549's profile

bonesbr549

1176 posts in 2526 days


#4 posted 03-20-2016 05:06 PM

Looks like the others have answered your questions. you only need a piece of material bigger than the part you are curring + the any extra for tool path (outside) and any hold downs.

I don’t know what you are using to control your cnc machine with, but it should run on G-Code. Sketchup has a plugg-in that will convert a 2d vector to a g-code map. You need to pick a post processor suppported to make it work or some minor tweeking. I’m running Mach-3 for control, so a majority of the options out there support it.

I’m just getting into it, and am building my cnc now. I’ve been playing with cad/cam for a while. Another option that I have been working with that I’m liking more and more is Autodesk fustion 360, which is free for a hobbyist. learning curve is quick, and it’s native output to cam makes it a big plus!

Another big popular one out there is V-carve Pro and Aspire by vetric. The are not free and do cost some money. V-carve pro will handle most needs, and is not cheap but similar to sketchup pro in price. Aspire is very expensive

I’d suggest you look into fusion 360. Tons of videos on youtube and will get you what you need. Just find out what your cnc is running for control and make sure it’s supported by what ever you use. Good luck

-- Sooner or later Liberals run out of other people's money.

View Logan Windram's profile

Logan Windram

303 posts in 1921 days


#5 posted 03-20-2016 08:33 PM



Looks like the others have answered your questions. you only need a piece of material bigger than the part you are curring + the any extra for tool path (outside) and any hold downs.

I don t know what you are using to control your cnc machine with, but it should run on G-Code. Sketchup has a plugg-in that will convert a 2d vector to a g-code map. You need to pick a post processor suppported to make it work or some minor tweeking. I m running Mach-3 for control, so a majority of the options out there support it.

I m just getting into it, and am building my cnc now. I ve been playing with cad/cam for a while. Another option that I have been working with that I m liking more and more is Autodesk fustion 360, which is free for a hobbyist. learning curve is quick, and it s native output to cam makes it a big plus!

Another big popular one out there is V-carve Pro and Aspire by vetric. The are not free and do cost some money. V-carve pro will handle most needs, and is not cheap but similar to sketchup pro in price. Aspire is very expensive

I d suggest you look into fusion 360. Tons of videos on youtube and will get you what you need. Just find out what your cnc is running for control and make sure it s supported by what ever you use. Good luck

- bonesbr549

Thank you, Bones- very helpful tidbits

View Ger21's profile

Ger21

1047 posts in 2590 days


#6 posted 03-20-2016 10:30 PM

For most woodworking parts, simple 2D drawings are all you usually need. A very popular 2D CAD program is Draftsight, which is free. It’s very similar to AutoCAD. You just need to draw the outline of your part, and save it as a .dxf file.

-- Gerry, http://www.thecncwoodworker.com/index.html http://www.jointcam.com

View oldnovice's profile

oldnovice

5721 posts in 2827 days


#7 posted 04-08-2016 05:44 AM

I use Vetrics PartWorks which can import many different file types, PDF, dxf, and others.
But it also has an interface that allows creating tool paths on drawings created in PartWorks!

-- "I never met a board I didn't like!"

View brtech's profile

brtech

893 posts in 2382 days


#8 posted 04-08-2016 01:51 PM

You need to know what the capacity of your school’s machine is. Everyone is assuming that if it can accomodate a 4×8 sheet, it can accomodate a 2×4. That’s true IF the machine has 4×8 capacity in the first place. Lots of CNC machines are much smaller. So ask.

I haven’t messed around with the latest direct gcode from Sketchup plug in, but when I did it a while ago, I was pretty disappointed. It worked much better for me to output a DXF from Sketchup and then use another tool to go from DXF to gcode. You need the pro version of SU to output DXF though. Your instructor may have the professional version, so you might be able to get her to help you with the conversion. I think SU is a fantastic tool, which I heartily recommend UNLESS you have a lot of experience with AutoCAD or similar older CAD systems. If you do, the learning curve on SU is pretty arduous. The model is really different. But if you aren’t an AutoCAD wiz, then learning SU is easy and the tool is awesome.

View oldnovice's profile

oldnovice

5721 posts in 2827 days


#9 posted 04-08-2016 08:35 PM

If you use/have almost any of the Vectrics CNC software you can import almost any 2D file for sheet cutting!
I use PartWorks 2D program for sheet, 2D, work and PartWorks 3D for carving work.
Obviously, PartWorks 3D uses 3D object fikes for carving.

Nearly every CAD program can supply 2D files and 3D files which can be used by Vectrics software.
Additionally, Vectrics has drivers for nearly every CNC on the market and “G” if so desired!

Obviously, the full versions of Vectrics applications can do much more than my scaled back versions and I will eventually upgrade to Aspire from Vectrics but currently I am happy with the ones I have now.

Basically, you may use/choose any CAD application with which you feel comfortable from both a cost and learning curve perspective.
You may also want some artis tic creation software for making carving files.

I use the free version of Creo Elements/Direct Modeling Express from PTC which creates PDF 2D files and STL or STEP 3D files. It has all I need!

I do not have any art creation software!

-- "I never met a board I didn't like!"

View ArtMann's profile

ArtMann

131 posts in 275 days


#10 posted 04-09-2016 12:01 AM

I have use Sketchup to design solid models for direct importing into Vectric’s Vcarve Pro. Vcarve Pro is a modestly priced design and toolpath creation program that is very popular. That may be what the school is using. I believe PartWorks 2-D is just Vcarve Pro that is supplied with Shopbot brand machines but only works with their equipment. To be successful with the import to a 2-D model, you have to create the Sketchup model specifically to Vcarve requirements. It isn’t exactly straightforward, although it is worth the effort to learn IMHO.

The above description is a 2-D import suitable for machining flat parts. There is also the possibility of exporting a true 3-D model as an STL file and then importing it into Vcarve as described above. That is not advised in this case. True 3-D models are cut using an entirely different strategy than 2-D models. You definitely do not want to go that route fo r cutting out plywood.

As someone already mentioned, the machine can deal with any rectangular material that is less than or equal to the capacity of the machine.

View oldnovice's profile

oldnovice

5721 posts in 2827 days


#11 posted 04-09-2016 02:39 AM

Artmann, there are methods of cutting pieces larger than the working envelope of a given CNC.
Indexing the material can be done to increase the cutting size can be done on most any machine.
Here is an example of a 60 inch long piece cut on a 25 inch size machine, see post #2 for specifics.

Indexing to te next location(s) has to be precise and I have yet to see indexing in both X and Y at the same time.

-- "I never met a board I didn't like!"

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