Shopping for a CNC Machine for Window and Door Construction

Accuracy and hold-down effectivess are key attributes for good mortise and tenon machinining in solid wood. June 29, 2009

I am looking into our first CNC for Window and Door Making. I have been promised a lot by sales people such as repeatable accuracy but I would like to put the question out to the folks here. We do mortise and tenon joinery so this brings its own set of headaches to the table.

Obviously the baseline will be a Pod and Rail system. The purpose of this approach is to handle the part less, thereby increasing accuracy and less work in the assembly area. The other approach would be to continue with the same old shaper tenon setup. Lastly - new or used?

Forum Responses
(CNC Forum)
From contributor B:
Right up front the bottom line here is that a CNC router can do most everything, but it is not necessarily the best tool for everything. I've said this again and again over the years. A good quality router can be a significant expense. If mortise and tenon work is the only significant process you are looking to do on a CNC, then perhaps you should look more closely at alternative options such as dedicated industrial mortise and tenon machines.

If you have more uses for the CNC then of course that would change the equation. To answer your question any quality machine from Shopbot on up will give you accurate repeatability. I believe you are probably looking at Point to Points as vs. routers so low cost routers are not going to fill your need. I've not seen a "light weight" Point to Point so you are probably looking at the "heavy iron" machines. I would think that any well know brand should give you the quality level you require. Look to service and support as major deciding factors.

From the original questioner:
The use is not for just mortise and tenon work. Radius and a "whatever I want" design build mentality is what I am looking for. Sure bread and butter stuff pays the rent but the ability to create the "perfect part" is key. I have spoke with a few sales folks and then their clients and have heard a lot of discouraging news as far as support and the accuracy being off consistently up to a millimeter. Thatís unacceptable for a 250 k plus machine. Sales people wanting to close the deal any way they can is dangerous and there are more than a few bad people out there.

From contributor J:

I looked at door and window routers for three years and decided to stick with tenoner and shapers for now. The cost to do it right for building the complete door was getting overwhelming for my 2-3 man shop. Youíre right, pod and rail is the way to go for this type work.

Homag is a good machine for doors and windows. I went on the Stiles European tech tour for doors and windows. I would recommend that. Most European makers offer tech tours also. Other brands I looked at and liked were Beisse, Busellato, SCM and Holzher. Because of the complexity I think any router can have accuracy problems. Good service is the key.

Mortise and tenon construction will require a stout machine if using tenon heads. Look at the tool weight capacity of the machine to see what type tenon heads will work. And tool changer capacity. Biesse has a machining center called the Uniwin that can take monster tenon heads. It is like a router and tenoner combined. (Very expensive)

When I looked at machines, software and tooling I figured for a new machine for this type work minimum 150K to 250K, software 40 to 75K and tooling 35 to 50K. Not counting the time for learning curve. I already have insert tooling but most of it is too heavy for routers in my price range. Itís true you can do a lot with the proprietary software these machines come with but to really optimize production third party software is needed. SCM, Biesse and Busellato have in house door and window software for the European market but it is not developed for the US yet.

Itís pretty impressive to see a well optimized router totally machine a complex door or window and I have not given up on the idea. I may eventually get a used lighter weight machine to do hardware routing and curve template work. I donít own a router and these are just my opinions but I would look at all costs and talk to other owners before you plunge. With the right product and volume it can work. There are a lot of used machines on the market now.

From contributor B:
The accuracy is far more dependent upon the hold down system then repeatability of the machine itself. Any CNC that is not repeatably accurate to a few thousandths is not going to be a quality machine. Most any name brand will fulfill this requirement.

Hold down is probably the trickiest part of wood parts CNC work. We cut hardwood parts and I know firsthand about wood movement on pods. As you look at various brands this is a key point you need to examine. Make sure they show you how their hold down pod systems will keep the wood solidly in place.

From contributor A:
Machine accuracy depends on the skill and accuracy of the person programming and setting it up. Yes there is the odd machine problem but in my 14 years experience with routers of many brands, majority of the time it's a setup issue. This may include tool setup as well as proper fixturing of the part. I suggest you look at buying a used machine, there are many out there these days and go from there. SCM, Biesse, Homag are all good machines and the service is the same in terms of price for all.

From contributor G:
We have a Homag 311 window/door machine. It has special clamps for window components and we achieve 0.1mm accuracy. The machine is built like a tank even when our operator makes a mistake the machine does not break. Homag now also has a "power profiler" machine just for window and doors. Eemember that windows and doors need lots of different tools left and right. We have a Flex 5 unit that has eliminated several tools. I can't say enough about support either our experience has been top notch!

From contributor B:
I would have to agree with the comments getting a Delmac or an SCM CNC. They are both owned by SCM Italy so are practically the same machine. In my experience, our Busellato has been a work horse. We run it two shifts per day and have been doing that for four years with minimal brake down and problems. I could only expect the same if you went with a SCM machine like a Routech. They are all build to last with the best technology

From contributor W:
We have both a Routech three axis and Busellato five axis for window and door manufacturing. The Busellato Genesis software is incredible. The difference for creating templates for stiles and rails makes it possible to create programming for a 100 window job in under an hour. The pod/rail system is needed but the stiles and rails for the sash are so narrow it is tough to hold a part onto the pod without movement. We typically use the clamps for window parts and mill three sides (over by .125 then assemble and put the entire sash up in the clamps and size and edge prep the sash completely). This saves a lot of set ups on shapers, etc.

From contributor D:
I use the Biesse Rover, it has taken me two years to get my personal accuracy up to par with the machines, but now that I am all caught up I am within the tick on my tape measure for sure. I build doors, I am starting to mortise and hinge them now, all is looking good so far.