Programming CNC Equipment from Templates

Advice on "teaching" a CNC to cut out the shape that corresponds to a site-made countertop template. July 29, 2007

Iíve been considering a CNC for some time now. Besides just using it to produce cabinet parts I would like to use it to help me cut out solid surface c-tops. If I spend this much on a CNC I will not have enough budgeted for photo templating software or a laser to take field measurements. I don't mind making templates like I have been out of masonite or particle board but once I get them back to the shop is there a good way to edge trace them with the CNC? Does it take a long time to do this? Also is there anything out there where you can lay your template on the CNC table and take points by using a hand held device like an ink pen to tell computer software the perimeter of your top?

Forum Responses
(CNC Forum)
From contributor A:
I'm not sure which machines have this option but I do know that the AXYZ machine has this feature.

From contributor B:
I never knew there was anything out there that would read a full size template like a scanner does a document, then cut it out on a CNC. Please give me more info if this is possible. I thought you would need to draw it out in some Cad program.

From contributor C:
I have never done it but I think that most, if not all, CNCs can digitize a template if you traverse the machine to specific points on the template and enter the locations in as you go. The more points you enter, the more accurate the parts are. You should consult the machine manufacturer and they will fill you in on the details. There could also be some new things out that would make the process easier.

From contributor D:
I'd consider getting a digitizer if you are going to go the CNC route. Digitizing templates on a CNC is not the most cost-effective use of the machine and/or operator.

From contributor E:
If you need to wait for a digitizer system, you'll probably be better off drawing the templates in the Cad program. You may be able to add the template into the lease for the CNC. Find a good supplier of slow helix tooling for cutting solid surface on the CNC.

From contributor F:
Check out MultiCam - they offer both 2D and 3D digitizers as an option. This option is quite popular with countertop manufacturers. As you well know, most walls are not square in a house. The template/2D digitizer method is the next best thing to a photo template system. I believe this is considerably less expensive than a stand alone digitizer as an option. But, as mentioned, it may not be the best use for your new router.

From contributor G:
The low-end solution is to take a digital photo of your cardboard/hardboard template and trace it in AutoCad or some other program. If you can get a straight shot of the template, without angled camera distortion, and you can refer to measurements on the template, you can get a pretty accurate layout on the computer to send to the CNC. After you have done this a couple of times, you can do some fairly complex stuff.

From contributor B:
I do this type of stuff on a PRT Alpha Shopbot with a digitizing probe attachment all the time. The Shopbot is not a bad machine these days. I do countertops, cab parts and upholstered furniture parts in large quantities - over 150,000 parts so far.

From contributor H:
Do you use water with your Shopbot? I thought most solid surface product cutting needed water?

From contributor A:
I think he means materials like Corian and such that are like plastic and will cut with a router bit - not stone based stuff that needs a water jet.

From contributor I:
If you calculate the cost of materials and the transporting of the materials to and from the jobsite to create a template, and then the cost for the upfitting of a digitzer either on the CNC or some other form of a digitizing system, the time it takes to gather the points and reverse engineer the information to get to the point of having a drawing that can be used to create the parts on the CNC, you will be going on and on just like this sentence.

We used to do our templates with cardboard, templast or plywood strips depending upon how they were being transported and what type of material we were fabricating. Not anymore. No more vans or trucks to transport templates or worrying about whether or not it is going to rain and soak what is in the back of the pickup. No more problems getting in and out of high rise condos or finding a parking space big enough for the truck itself. No more fighting with the elevator operators and management because they don't have a freight elevator to transport template material to the job. No more hot melt or contact adhesive to purchase and or deal with on site. I could go on , but it comes down to this - we have a two photo template kits and two FARO arms. Some jobs actually are better one way versus the other and it depends a lot on who is going to process the information after measure, but there is no way that I would consider purchasing a CNC without including the cost to have at least one of the methods we use to create the templates. They allow for information to be emailed from the field measure person to the office to begin processing immediately if it is necessary to keep a project on schedule. This method also allows us to reduce travel time depending upon how large of an area that needs to be covered by centrally locating an individual in an area that we work in and communicating job and template information back and forth without needing to pay the extra expense of transporting templates back to the office at the end of the day. Another benefit is that the template system allows us to measure projects for materials that we do not fabricate, but do install, and send the jobs by email to the fab shop to be cutout and delivered back to us completed.

I won't say that the methods we use are cheap, but they have paid back our investment many times over. And the best thing is that if you have someone who truly understands cabinets and countertops and has some skills on a computer, the learning curve is not too difficult. I had no CAD experience and only a limited amount of experience on the computer. Once I got the basic ideas about how to create the parts in a CAD program, I have been able to make every other part of our operation more effective and allow anyone that has to deal with our customers to have access to the same file information that was created during the field measure. It has also made it easier to create many different design options for the customer to preview before the project went into fabrication. The truth be told, in the time it took to type the response, I could have either done a field measure or processed the after measure info for final fabrication (actually as badly as I type, I could have done both).