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View Full Version : Appropriate CNC Router



mike wallis
07-27-2007, 7:08 PM
Hi Everyone, I'm trying to find out the most appropriate type of CNC Router to use for a particular application. What I'm trying to accomplish is to route out standard plaque sizes such as 8x10", 9x12", etc. about 3/8 of an inch down in order to inlay a marble plaque into them. The one problem I can foresee is getting the corners squared off so there's no radius. Is it Possible to get a squared edge with a CNC router?
One CNC that comes to mind is the CarveWright, it's the perfect size for the plaques I'm looking to do and the price isn't bad either but there are mixed reviews on it. Is there a more suitable CNC for these small plaques?
I should also mention that the plaques will already be finished so I wouldn't want any marks on the finish from the CNC process.

Thanks' for any and all help!
Mike Wallis

Mike Null
07-27-2007, 7:44 PM
You can always use a corner chisel to square up the corners. If this isn't high volume a router and jig will do the job.

pete hagan
07-27-2007, 8:25 PM
If you have any real volume I'l go for a mortice chisel / power chisel unit like this http://woodworker.com/cgi-bin/FULLPRES.exe?PARTNUM=14-651

If you do any amount of woodworking this thing will make life a dream!

Pete

Bob Reda
07-28-2007, 8:35 AM
Mike

If the pocketed area is not that big, Vcrave pro software can make you the square corners with a v bit. I'm saying that the area will take a while to pocket out because you would be using a v bit. But you can't use this software on a Carvewright/ You may be able to pick up a used benchtopo model of a shopbot.

Bob

mike wallis
07-28-2007, 10:55 AM
Mike, the chisel is a good idea. I do believe that I will be doing a good amount of volume so I may need something a little more automated.

Pete, you really got my attention with the mortice chisel. However I'm not sure how the process works. Can you give a brief explanation on the process?

Bob, this also sounds like a good idea. The maximum routed area will be 8.5x11", how long time wise do you think that would take with VCrave Pro?

So so far ShopBot and Carvewright are the two CNC's that may do the job. Is there any other small CNC's out there that may work for this application?

Thanks again for the responses.
Mike Wallis

Rodne Gold
07-28-2007, 2:05 PM
On the bigger CnC's , the software comes with a corner sharpening routine. You would hog the major proportion of the inlay and then change to a V bit.
However this wont really work as a sharp corner is at the surface of the plaque and the wood slopes to the bottom of the hogged out section and will interfere with inlay.
You could hog with a big bit and do a simple outline finishing pass with a very thin straight bit and minimise the radii , a 1.5mm bit will have a .75mm radiused corner and thats almost nothing to speak of. prolly easier to hog the hole a little outsize to compensate
So it would be a 2 part operation requiring a bit change.

I would definately look at the cheap semi heavy duty CnC routers coming outa China for this type of job .

Mark Winlund
07-28-2007, 7:56 PM
You might consider the SR-23 by Camaster. It is a 2' x 3' capacity router with professional features. All axis are ball screw/ball nut, and the ways are all linear bearing. It comes with a 2hp spindle that is VFD driven, not a converted brush type consumer router. I have done a lot of looking, and this one comes closest to the big cabinet making routers, but in a small size. I have one on order, and if anyone is interested, I will give the forum a review when I get it. I have ordered an upgraded 3hp water cooled spindle for it along with WinCNC software and a somewhat upgraded computer to drive it. Total cost about $11,000. I used to have a professional Northwood router with three spindles, but it was serious overkill for what I do now (awards). The controller was 8 years old, and a lot has happened to the technology in 8 years!

Many of the smaller/lighter routers cut corners in the drive and bearing components.

Mark

Leo Voisine
07-28-2007, 8:09 PM
I am somewhat new to CNC router myself. I have a Larken 2424 Camtrol CNC router.

Brand makes no difference. Tool geometry makes no difference.

A router - ro matter who manufacturers it. Software - no matter who makes it. I have V carve Pro - awesome software.

Still - a router is goint to hold a round bit no matter what. The smallest bit is going to be round and WILL leaf a radiused corner.

You can square the corner by hand with a chisel, but any and all routers will leave a radiused corner.

I am new to CNC routers, but I have been in machining for 30 years. This is exactly the same as machining wood on a vertical machining center.

Steve knight
07-28-2007, 10:59 PM
depednig on the machine and how well you can hold the piece in place you could remove that stock in about 4 minutes. thats at 200 ipm. on a decent shopbot you could do it at 400 ipm.

Doug Griffith
07-31-2007, 12:09 PM
The last time I looked the CarveWright basically provides you with "templates" that you can manipulate to your needs. This may not be what you want. It also cuts like a plotter. Going back and forth while the material moves through the machine. That means it does not cut on the X and Y axis like other CNC machines. Larken makes a pretty good CNC that is only 24" x 24". I have one and am quite happy with it. It's got stepper motors though so keep that in mind.

mike wallis
07-31-2007, 1:28 PM
Thanks again for the replies. I got a quote yesterday for a 24"x24" router/engraver and almost fell over, $17,000.
Rodney I'll defiantly be looking into the Chinese CNC. I really only need the router for one task at the moment and most of the CNC's out there are really over kill for the job.
It's hard for me to believe that the Carvewright can't hog out a simple 8.5x11" rectangle 3/8" down. Any one out there with a Carvewright that has done this type of cut? I'll check the CW forums as well.
Thanks again

kipp yeakel
07-31-2007, 1:47 PM
I have a carvewright, and yes it can do this. However, the carvewright is not a production machine, and not sold as such. The carvewright can do a cut out(vector mode) without doing it like a printer(raster mode) as well. I'd look into the shopbot or similar for any production work.

Kipp

Pete Meacham
07-31-2007, 2:10 PM
Mike

Don't go Chinese. Big mistake in my opinion for support and quality reasons.

Take a look at the ShopBot Benchtop line of CNC machines - they will do exactly what you want and won't take up much space. You will certainly get better support from the ShopBot company and the ShopBot user community (Forum) than you ever will with an off-shore product.

And you can get a very nice model for MUCH less than the $17K depending on the options you chose.

Do yourself a financial and support favor and check them out please.

www.shopbottools.com (http://www.shopbottools.com)

Pete

Keith Outten
07-31-2007, 6:57 PM
I think you may be able to get a benchtop ShopBot for under $9,000.00. Visit their web site for the latest prices and details.

www.shopbottools.com

Woo Hoo...there is a benchtop for $6,995.00

http://www.shopbottools.com/prSalpha.htm

Bill Cunningham
08-01-2007, 12:24 AM
This must be Chinese stuff sold from Canada, on ebay.. They 'do' say they have a 1 year 'replacement' warranty for both the laser (3 mo. on the tube) and the CNC. The prices certainly are cheap.. But, I assume you get exactly what you pay for.. maybe less.. But, if your near Toronto, and your curious it might be worth a look..

http://search.ebay.ca/_W0QQsassZrawanat

Doug Jones from Oregon
08-01-2007, 12:49 PM
Mike, I'm also looking into purchasing a "small" cnc router, mostly because the projects I have in mind do not require a 4X8 format and I can no longer throw full sheets around like I once did.

You might take a look at digirout (also their url), they have some very attractive prices and are US made. Don't know if I will go this way or not, still really drawn to shop bot....for me the biggest challenge seems to be finding a software CAD/CAM package I like, I was so spoiled by Alphacam when I was running 3 full size routers 20/7 a few years ago.

Doug

Larry Alles
08-01-2007, 4:18 PM
Your can't get a square corner with a round tool bit unless the tool is very small. 1/16" or smaller and then you still have to square up the corners

Keith Outten
08-01-2007, 6:24 PM
Larry,

You can get an inside corner that does not have a radius with a V-bit. The V-bit rises as it moves out of the corner thus leaving a sharp corner with no radius.

.

Bob Reda
08-02-2007, 5:34 AM
Larry,

Shopbot is comming out with a new benchtop model, so there may be quite a few people you are going to upgrade and have some of the older models up for sale that will probably be at a good price. Monitor the shopbot site and they have a section for sale items, it always has something in there
Bob

Mike Kelly
08-03-2007, 11:12 PM
Mike, you can get square inside and outside corners with v-carving techniques. Here is a picture of an idea of what you can do.

You can get a ShopBot Benchtop with router for about $5,000. Look at the new Benchtop they are coming out with. http://www.woodshopnews.com/movies/shopbot.wmv

Ted Hall says it is $3795 for the entry level machine. If that is true it will blow away most of the competition at this level. It is a sweet machine from the looks of it. It incorporates the new PRS gantry which is a real step forward. They do not have this machine advertised on their website yet, but it is not far off I suspect. It will take up the space of a cabinet saw.

Keith Outten
08-04-2007, 4:56 AM
Mike,

Thanks for the link to the video, The new ShopBots keep getting better and better and the small machines will make a quality CNC machine available to more woodworkers. When the large format PRSalpha machines started shipping early this year there were lots of people upgrading and plenty of older machines for sale at vary resonable prices.

I recently contacted ShopBot to ask questions concerning machining brass and stone. We have a large project at CNU and were considering doing the job in house but my schedule is full so we are outsourcing the job. I was surprised to learn how easy it is to machine soft metals with a few precautions.

I picked up several jobs for my personal ShopBot this week, you gotta love them Bots :)

.

Leo Voisine
08-04-2007, 3:16 PM
Well - like I said I am still new to CNC routering.

I have a Larken Router 2424R

I also have V Carve Pro - I cannot say enough good about that Vectric stuff. Definately a MUST have. Service is the absolutely BEST I have ever seen in my life.

Anyway - YES - you CAN engrave square corners in letters with v groove cutters and the right software.

Go to the www.vectric.com (http://www.vectric.com)

AL Ursich
08-04-2007, 8:32 PM
Mike, I have 2 Sears Compucarve machines and 2 older Laser Engravers. I would think that the Carve Machine could do the slots but not the tight joints. What about using a Laser Engraver to cut the grooves?

The Carve Machine is great for photos. With the Centerline Text a great tool for 2K. You can play with the software for 30 days free. www.carvewright.com (http://www.carvewright.com)

AL

mike wallis
08-07-2007, 10:55 PM
Sorry for the delay in response, just migrated to a new computer in the last few days. Seems like it takes longer each time.

The new shopbot bench top model looks real attractive, especially with my space issue.

Question: The V-bit, when the corner is cut dose it slope down at an angle dept wise? Hopefully I'm making sense.

Thanks' Kipp, I'm not sure if what I'm going to be doing is production, Maybe 2-3 Plaques cut a day. Production wise what limits the Carvewright?