Whether to Buy A Larger-Table CNC
Small table sizes can be limiting. Here, CNC owners offer various reasons for investing in a 5x12 table. March 4, 2009
Question
We currently own a small CNC (4' x 4') and have made the decision to purchase a new Weeke from Stiles. When we first started this process I was looking at 5 x 12 models, after getting the prices and looking at what our shop does, commercial p-lam casework, I am wondering if a 4' x 8' machine would be the ticket. I would hate to buy too small, however 98% of our work has always been with 4x8 sheet goods.
We do not fabricate solid surface, and all tops are cut on the panel saw. So how about it, what size seems the logical choice, do you buy large for the few times you may need it, or stay small for the vast majority of your work?
Forum Responses
(CNC Forum)
From contributor M:
I would never consider a machine less than 5' x 12'. When you consider the cost over the life of the machine, it is well worth it for those times when you really need it. Trust me, you will need the length, or the depth, or both at times. We do solid surface here occasionally, but we also use a lot of 3' x 12' particle board for c-top cores. We also run lots of lumber that is up to and sometimes over 12'. Buy big and grow into it. During tough times, you may need to produce for different clients that require a larger table size.
From contributor T:
5 x12 is the absolute minimum for any shop producing cabinets, tops and associated goods. We also thought the same years ago and five years later what a mistake a 4 x8 would have been. You may be doing your tops on the saw now but wait until you get the right machine. You will be wondering in a few years how did we do without this. 5x12 allows you to process 5x8 sheet material which really works out good for yield.
From contributor I:
If you look into optimizing software (assuming you don't have it now) you will likely find that your best yields will come from 5x8's and 5x10's. I agree with contributor M and T that you would regret not getting the larger machine, because you will eventually find ways to utilize the added capacity.
From contributor E:
I would tend to disagree with the above posts. I have found that some people overbuy on machinery and never use all the bells and whistles they purchase. This can be the case when you buy for the future but don't have a solid plan for how to get there. I think that you should buy for today, with a little wiggle room for expansion. When things get rough, you aren't paying for something you don't need or use.
I have also found that rule of thumb holds true : 4 x 8 is the optimum size for sheet goods, especially for standard cabinets; 5 x 10 is optimum size for MDF doors; 4 x 12 is optimum size for SS C-tops.
From contributor M:
Good points. I too have seen some shops that overbought. Unfortunately I have seen even more that bought a machine that just doesn't have enough features to get the job done well. The buyer should have a feel for whether or not they can grow into a machine, or if the basic features are all they are going to use. If nothing else, a machine with a big table and multiple working units on the tool plate will be easier to sell if that time ever comes.
From contributor B:
I have often thought that the size of our machine was a little overkill also. It's a 5X14 and has a 10 Station Tool Changer in the rear. We do mostly 4X8 sheet goods Cabinets and etc but sometimes we cut small parts. Those times are when I appreciate the size of the machine. I can run other jobs on the rear end of the machine and not disturb the set-up of my 4X8 spoilboard for sheet goods. It's almost like having two machines in one. It's small when you want it to be but very large when you need it to be also. With eight Vacuum zones it is very versatile. So bigger is better for us anyways.
From contributor R:
Part of the equation has to be the actual working area of the machine too. You don't want to buy a 4x8 machine to find that some of the tools can't quite reach some of the edges. 5x10 has become something of a standard bed size because it works for most customers - 5 x 12 if you want to do solid surface work.
But think about what you bought last year for sheet goods, and think about where you are taking your business. If you brought in one sheet of 12 foot material in all of last year, do you really need a 12 foot bed?
From contributor F:
Are you nesting or pod and rail? If pod and rail, go big. The center "safety zone" eats up about three feet when you run parts in pendulum. Also, as stated, make sure all drills, cutters, heads, etc. can reach every bit of the 5' x 8'. I have found that isn't the case always.
From contributor T:
Commercial p-lam casework does not fall into the 4x8 sheet goods for standard cabinet category. Normal commercial work can be far from standard in sizes and configuration. Also included in the commercial casework venue are reception stations, etc which never seem to fit the 4x8 profile - far from it at times.
All the major issues of high dollar components of CNC manufacturing have nothing to do with table size. Table size is just a few more feet in either direction of frame and bed. Yes, the rails/rack/screws are longer but that's about it. I can take my Multicam and shrink the overall to 4x8 and never change a critical component. Going from 4x8 to 5x10 is long from overbuying, most of the time it makes good sense. I have yet to encounter one individual over the years who said he wish he had a smaller machine. It's usually the opposite.
From contributor B:
Do yourself a favor and find out if larger material is readily available in your area. If it is, yield will generally be better with larger material, and if it is not available, you would be better off with a smaller working field. If larger material is available in your area, be sure to get materials handling options with the machine, if you go with the larger machine. Large materials and bad backs are a likely combination without material handling, and no one wants a workman's comp claim to deal with.
From contributor L:
Our first machine was a 4x8 - a good machine but too limiting. We are a commercial only shop. Most suppliers stock or can get up to 5x12 bd. Our current machine is a 5x10 bought used. Good machine but it would be better if it was a 5x12. 5x mat'l usually optimizes better. Lots of commercial work requires curved reception, nurse’s stations, and conference tables etc. That exceed the capacity of a 4x8 table. As for loading, if I were buying a new machine it would have an auto-load, unload system. If the cost seems too high, I would at least have a jib or gantry crane and vacuum lift. The push off and vacuum systems seem like a good unload scheme, especially if you put a down draft system where the work is pushed off. If you change materials often a gantry crane that can reach multiple units of material will save time and the hazards of using a forklift all the time.
