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View Full Version : Is CNC the answer ???



Harry Radaza
07-08-2008, 11:43 AM
hi all. I'm from the laser geeks. We manufacture fashion accessories using the laser engraver to engrave intricate designs. We would like to be able to create 3D carvings of florals, animals, text, artwork, onto various substrates. Materials used would mostly be wood, MDF, Acrylic, Shells. But mostly wood.

Size of the materials is normally between 2square inches to 4 square inches.

I have been reading lately about shopbots, carvewright and the shark etc.

I am wondering, for the 3d carvings that we need, if a CNC is the answer. And if so, what would be your recommendations as to the type and brand considering our needs and the size of materials that we work with.

Kenneth Hertzog
07-08-2008, 3:40 PM
Harry
I've been waiting to see what other people have to say also.
since no one replied I will.
One inch to Two inch square is pretty small for any of the CNC machines
you listed. I been using A sherline Mill (cnc) for about 5 yrs. now and it would
seem that this is more the size you should be looking to use.
won't the laser do 3D with the proper color setup?
Ken

Joe Pelonio
07-08-2008, 4:00 PM
The laser can do 3d with 3d artwork files, but is limited as to the depth. There is no setting for the z axis as on a CNC, but rather that is determined by the laser's power and the material. Doing 3D on a soft wood for example, would be much more effective than on a dense plastic such as acrylic.

Keith Outten
07-08-2008, 9:35 PM
Harry,

You can do what you want with a large CNC router but it sounds like it would be overkill given the small size requirements as Kenneth noted. I wonder if a rotary engraver would be an option? I don't know anything about the software they use but I'm sure there are a few people here that own them and might be able to share information about their capabilities.

.

Kevin L. Waldron
07-08-2008, 9:36 PM
I have been in a learning mode for almost a year learning the cnc that I bought. (Techno Premium class 5 x 12. Also several months back bought a big laser ULS 48x24 after the cnc there was not a learning curve on the laser, not that we know all but the laser software is realivetly easy after the 3d cnc software.) I had never done any automated machine work before a year ago. I was very familiar with lathes mills etc just not computer driven.

Now to your question. The cnc will cut just about anything. We have cut metal, pearl, glass, tile, wood, any man made products from plastic- wood composits etc. even mat board, but the smallest practical bit is 1/32" probably a 1/16" is more realistic. You will find that a ball nose bit is used exclusively for 3d with the only exception being a roughing bit like an 1/8-1/4-3/8-1/2 end mill. In my experience the machine will actually produce a 3d carving faster not changing bits, and I do have an auto tool changer.

You will need a software program like Artcam, Enroute, Visual Mill,Cut 3d or the like, pretty pricey software to do 3d work. The other thing that the cnc folk don't tell you is the time that it takes to produce a detailed 3d object. I recently did the last supper 12 x 18 = 6 hours, 18 x 30 = 11 hours. What you are describing would take far less time 2 x2 would probably be 7 or 8 minutes for comparison.

Problems with the cnc vs the laser are hold down. The nature of the router is that it wants to push whatever your cutting off of the table or pick it up or shove it down. That said your greatest challenge may be to designing jigs that hold your objects steady and firm while cutting and the smaller the object the more difficult to hold and yes we have large vacuums. With the laser it never touches the object and if you have a good exhaust table with vector cutting board it will tend to suck the item to the table and not move. We have done several 3d objects on the laser and time is relative, to the laser guys it takes a long time to do 3d on the laser but to a cnc guy there is not much difference. It does take a software program like Artcam to produce a 3d laser file in a 8 bit tiff gray scale format. Other programs may do this, I'm just not aware of any.

If I where asked would I go the same route that I went a year ago? I would probably make the same choice and buy the cnc first and then the laser. I probably would buy a much less priced cnc and spend more on a larger laser 4 x 8 maybe. Which will probably make me more money..... probably the laser unless I want to make cabinets for a living. Both machines have a lot of potential but with the economy being soft and we didn't already have a market I would go for the laser. We would probably be broke if we had had to borrow for the equipment.



If I can help further contact off site.

Kevin

Larry Bratton
07-08-2008, 9:42 PM
I think that you might want to think about a CNC engraving machine, like a Vision or Roland, if your only interested in doing items that small. Tool path clearances would be an issue for you with a large machine with say an 1/8" router bit. You can purchase engraving tools that will work with the larger machines, but hold down is then an issue. A Vision engraver might be just the ticket. Check it out. (I have one, but I haven't used it to do 3d). Try this link http://www.visionengravers.com/ The software for 3d is also a consideration.

Harry Radaza
07-08-2008, 11:38 PM
Thanks all for the responses. As for the jigs for hold down.... yes that can be a problem. I don't know if the cnc will cut all the way through. Say I had a 2'x2' sheet of MDF or wood. I can first do the 3d engravings an the whole sheet and then cut each 3"x3" pendant one by one. That would solve the hold down right?

As for overkill, we will actually have to go into production with these. Maybe 2,000 to 3,000 per design.

I have not really experimented with the laser 3d capabilities. Has anyone done so? In the meantime I will post another thread re 3d on the laser site.