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Forum topic by MrRon posted 976 days ago 1793 views 0 times favorited 24 replies Add to Favorites Watch
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MrRon

2727 posts in 1847 days


976 days ago

I would like to get your opinions on the use of CNC routers in woodworking. Conventional woodworking requires woodworking skills, whereas a CNC machine requires computer programming skills. Can we then regard CNC machines only as a production tool, and not to be considered as a woodworking tool like a saw or wood lathe.
I am building a CNC router from scratch as a woodworking project, but once finished, it will be capable of turning out work without any woodworking skill involved, only computer skill.


24 replies so far

View Sawkerf's profile

Sawkerf

1730 posts in 1672 days


#1 posted 976 days ago

I suspect that similar questions were raised when someone first connected an electric motor to a saw blade and rigged a table for it. , or when an earlier genius cut teeth in a piece of bronze and cut a board with a back and forth motion instead of whacking it with an axe.

Technology will always introduce new ways to do things. Some will embrace the change and others will bemoan the loss of the old ways. – lol

-- Adversity doesn't build character...................it reveals it.

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MrRon

2727 posts in 1847 days


#2 posted 976 days ago

I think I will be ok and not violate the rules of traditional craftsmenship as I don’t intend to use the machine for woodworking. I will be working with plastics, wood and aluminum, but not in making furniture or any crafts where skilled use of hand tools is needed.

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Sawkerf

1730 posts in 1672 days


#3 posted 976 days ago

Those “rules of traditional craftsmanship” were probably once thought of as radical ideas. – lol

-- Adversity doesn't build character...................it reveals it.

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PurpLev

8476 posts in 2252 days


#4 posted 976 days ago

bottom line, when you have a cabinet made, you have a cabinet made… does it really matter what metal cut it?

in some aspects, handwork can do certain cuts that computers still cannot, but as long as you make that cabinet in most cases it really makes no difference as long as the cabinet is well built and sound.

that aside – ‘A’ CNC router (as in not in a production plant where each CNC machine is doing 1 cut in a series of machines) will always take by far longer to produce a woodworking project when compared with non-cnc work where parts can be batched cut together and cutters like saw blades are used (faster than router bits cuts hands down).

so, there are pros and cons like in everything else in life. do whatever works for you. no right or wrong

-- ㊍ When in doubt - There is no doubt - Go the safer route.

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Green_Hornut

82 posts in 1224 days


#5 posted 975 days ago

I think first if you can define woodworking then this discussion becomes much easier. And of course you can’t so that is why we have such a divergent set of opinions. I myself still do my face frames with a mortise and tenion joint, mostly because I own a Delta mortiser and not a Kreg pocket jig. I join my boards with briskets because I own a DeWalt brisket joiner and it is quicker than cutting blind splines. Is what I do any less or more woodworking than the next person? If I made my mortise and tenion with a drill press and a traditional mortising chisel rather than the Delta would that be better woodworking and is either method better woodworking than a pocket joint?

I have been looking at CNC routers because it opens up new opportunities that my skill set will never match. I know folks who are fantastic carvers. I know that I will never be one. Will CNC replace professional carvers? How many professional carvers do you know? Cutting out a board that is 4 inches wide and 13 ½ inches long can be done by many different ways. What you do with that board is where woodworking defined.

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dannelson

140 posts in 975 days


#6 posted 974 days ago

mr ron, trust me as a cnc’er your woodworking skills will be tested . theres alot to know besides just sitting behind the computer and pushing buttons. we took the plunge almost two years ago and never looked back. I dont know if you do woodworking for a hobby or profit. we do it for profit. recently we cut out 400 piecesin less than 4 hours for our woodworkers guild toys for christmas. I cant imagine the time that would have be spent cutting all these pieces by hand. The cnc is only another tool in the shop. there will be plenty of hand work to follow. if you have any questions just feel free to drop me a line.

-- nelson woodcrafters

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DLCW

522 posts in 1258 days


#7 posted 974 days ago

A CNC router is just another tool in the shop like the tablesaw, jointer, bandsaw, etc. If used properly it can reduce the time it takes to do some – not all – tasks in the shop and increase quality and accuracy.

One area I found that the CNC REALLY shines is when I make bending forms for bent form lamination work. I used to do it by cutting the master, spending a long time shaping and sanding it smooth. Then I would rough cut a bunch more blanks and template route them on the router table until I had the form thick enough to do my bending. With my CNC, I program it to cut both sides of the form, put a sheet of 3/4” MDF on the table and tell it to cut the forms. 10 minutes later all the forms are no cut ready to be screwed together. Does this take away from the the craftsmanship of the final project – NO. It makes it so I can now do this type of work MUCH faster and more accurately. After all – is making a bunch of MDF templates craftsmanship or busy work.

I can also do 90% of a very detailed carving using the CNC and finish it with hand chisels to make it really pop out. Does this reduce the craftsmanship – NO. It makes this specialized type of work more affordable to many more people other then Bill Gates.

I produce plaques and cribbage boards for a local company. If I had to cut all the plaques and cribbage boards by hand there is NO way I could get this work because doing it by hand would be cost prohibitive for the customer.

For cabinetry – I can now take a sheet of plywood and turn it in to cabinets parts with mortise and tenon joinery, all shelf pin holes, drawer slide holes and other hardware mounting holes drilled, all ready to assemble in about 10 minutes – with .001” accuracy. Does this reduce the craftsmanship of the project – NO. It makes for a higher quality end product with a much quicker turn-around, thus saving the customer money.

The CNC does not take the place of good design or construction. It just makes some mundane tasks much easier and much faster.

So – does a CNC have a place in a hobby shop where time and money are not an obstacle? I don’t know. If I was a hobby woodworker I wouldn’t spend the money on one. In a professional shop it is getting to the point that you can’t be competitive unless you have one or have access to one.

-- Don, Diamond Lake Custom Woodworks - http://www.dlwoodworks.com - "If you make something idiot proof, all they do is make a better idiot"

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pariswoodworking

379 posts in 1089 days


#8 posted 974 days ago

A CNC has it’s place. Many people cannot carve well. a CNC is good for that. It will not produce the same results that a craftsman doing the work by hand can do, but it will still do the work. I beleive that it does has it’s place in fine woodworking.

-- Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. -- Albert Einstein

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MrRon

2727 posts in 1847 days


#9 posted 973 days ago

Dannelson: Can you explain to me what steps I take to go from start to finish? I do all my design on a PC using 2D Autocad. I know you have to convert to G-code with one program and then run the G-code on another program which controls the CNC router, but what else do I need between the PC and G-code program do I need. I’m thinking a laptop with the Acad file installed.

View DS's profile

DS

2131 posts in 1024 days


#10 posted 973 days ago

Wow! Where to start?

I’ve been in this business for a very long time. I’ve worked in shops with and without CNC machines. There are capabilities and limits to each machine and working within them to produce woodworking is just like working with any other machine. There are benifits and trade offs.

@pariswooworking: Not sure about your carving statement. Case in point – Raymond Enkeboll Designs. They have a team of Master Carvers who will spend months on a new peice. It is then digitized and mass produced on 5-axis CNC routers. The final dressing is done by hand with gouges. They are arguably some of the best carvings out there and they are relatively affordable when compared to strictly hand carved pieces.

The main difference to a hobbyist versus a professional shop is more software driven than hardware driven.
Good CNC software that will efficiently enable your wood working skills will cost 4 or 5 times what you might spend to build a hobbyist machine.

@PurpLev: I disagree with your statement that it will take more time to do a CNC part versus a traditional part. With hobbyist software this may be true. With PRO software, this is rarely ever true. I do one-off pieces every day at more than twice the efficiency of an AutoCAD, Sketchup, or other, manually drawn and produced piece.

@MrRon: The link from AutoCAD to G-code is the CAM portion of CAD/CAM. It is called a post processor. They usually read the layers of your AutoCAD dxf file to determine which tooling should be used and how. (Or, you can manually define the tool paths within the geometry.) The ones I’ve used run a lot of money, though I’ve heard of several at the hobbyist level that are reported to work well. Advanced CAD/CAM is integrated with “Screen to Machine” code generation which is highly automated.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

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SPalm

4760 posts in 2486 days


#11 posted 973 days ago

As DS251 states, you need a CAM program to convert from your drawing file (dxf, eps, etc.) to G-Code. This can be done upstairs on any computer. Fancy ones are $$. Big price changes if you want 2 1/2 D as compared to 3D (think cutting out and pocket/mortise as compared to carving).

Then another computer (controller) will take the G-Code file and send it to the motors (It could be the same computer, but does not have to be). Mach III is a very popular controller program for this. This is not the CAM part, but the controller part, if you don’t have this yet.
http://www.machsupport.com/

I use Vectric V-Carve Pro for my CAM, as it does what I want easily and without too much fiddling unless I want to. Good simulation too. Vectric also has an upgrade to 3D modeling. I don’t do that.
http://www.vectric.com/

Ger21 is a LumberJock and also a moderator over at CNCzone.com. Give him a PM if you want. He has written a free VB macro that you plop into AutoCad and it will do a lot of CAM conversion.
http://home.comcast.net/~cncwoodworker/AC2GC.html

I have not used it but another popular CAM program is CamBam. You can try it for free for 40 times and then buy. $125 for the 2 1/2 D style.
http://www.cambam.info/

Good simulation is really nice for a CAM program so you can ‘see’ the end result before you cut.

Good luck,
Steve

-- -- I'm no rocket surgeon

View DS's profile

DS

2131 posts in 1024 days


#12 posted 973 days ago

Very well said, Steve

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

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MrRon

2727 posts in 1847 days


#13 posted 973 days ago

Thanks Steve. You have been a great help. I’m getting closer to understanding this CNC thing. The mechanics is easy. It’s the computer part I’m weak in. Can I use a 2D drawing or do I have to draw in 3-D? The CNC components I’m going to use is for 3-axis. Does this mean 3-D?

View DS's profile

DS

2131 posts in 1024 days


#14 posted 973 days ago

Most controller software is 2 1/2 D—that seems confusing, but it is fairly simple.

Even though your machine has 3 axis’, most controller software can only interpolate two of them at a time.
That’s just a big word for ‘mixing’ the movements of two axis’ to do something meaningful, like a diagonal line or a circle. (think etch-a-sketch)
While it is interpolating two axis’, the third axis has to remain fixed, (hence the half axis). The interpolated axis’ can be a combination of any two out of the three.

To more directly answer your question, you can usually start with 2D CAD drawings and apply tool paths to it that have depth information. This works fine for most case goods parts.

It is fairly rare that someone will actually need true 3D interpolation and there is an entirely different genre of software to deal with this. If you are doing more free-form carving or artwork, for example, true 3D it very helpful.

The PRO systems I use start with true 3D solid models and convert these somewhat to 2 1/2 D for output.
When I place a shelf adjacent to a case end, it uses predefined joinery information as to how I joint a shelf to an end and automatically adds the operations for me.
For example, I use a blind dado euro box contruction method. When I add a shelf between two ends, it adds dadoes, construction boring holes and front grooming notches on all the affected parts without any extra involvement by me. That information is ready to convert to G-code with a click of the mouse.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

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SPalm

4760 posts in 2486 days


#15 posted 973 days ago

EDIT: I didn’t see DS’s entry while I was composing. Sorry to duplicate. @DS I want your System!!! @Ron Your AutoCad will generate DXF files which will work for 2D and (with a good CAM) 2.5D

Hey Ron, yes I know, lots (and lots) to learn here. I am just a hobbyist, but I have been fiddling with this for years. There are questions you will be asking that you haven’t even thought of yet. It can get complicated fast if you really want to work this thing. :)

OK – 2D vs 2.5D vs 3D vs True 3D. People use different terms, but the way I look at it is that you basically have these four situations. So it depends on what you want to do. (We won’t get into lathe stuff.)

2D – Profile cutting. Cutting out shapes. You need 3 axis cause you need to raise the bit from part to part.

2.5D – Profile + Pockets + Height control (+ maybe Vcarving). Cutting out shapes with rabbets and mortises with different heights. Cutting boxes like these out of solid wood. Doing gentle curves. Doing geometric carving. You need 3 axis.

3D – Cutting (carving) out things like a human face, or a deer, or a flower on a panel. You need a 3D CAD program to generate this to start with (or buy the artwork). If your AutoCad will not output an STL file, you will need to buy a more fancy CAD. You need 3 axis.

True 3D – Cutting out a human head. This is for sculpture. You need 4 or 5 axis because you need to get to the back and the top/bottom of the head.

Then their are special purpose things like photo engrave and V-carving that use special software to do variations of 2.5D things.

What do you want to cut with this? I just went to Vectric.com and they sell 5 products. Aspire and Vcarve have CAD with more advanced CAM. Cut2D and Cut3D are just the CAM converters. And then one for photo engraving.

Steve

-- -- I'm no rocket surgeon

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