LumberJocks

What problems does owning a CNC solve?

  • Advertise with us

« back to Sweating for Bucks Through Woodworking forum

Forum topic by Loren posted 08-20-2012 05:52 PM 2362 views 0 times favorited 20 replies Add to Favorites Watch
View Loren's profile (online now)

Loren

7808 posts in 2367 days


08-20-2012 05:52 PM

I actually know what major problems CNC would solve for me if
I had the space for a full-sized machine. I don’t though,
so I cut out parts with saws. I’m sure there are benefits
and hassles to owning a CNC machine I don’t know about
though, so I’m asking.

I’m curious about how people with CNC machines have
found efficiencies or new profit sources as a result.

An example would be:

“I found cutting out melamine cabinet parts with the CNC
machine minimized chip-out and required less time than
keeping a scoring saw set up and maintained.”

-- http://lawoodworking.com


20 replies so far

View Doss's profile

Doss

779 posts in 984 days


#1 posted 08-20-2012 06:11 PM

Loren, what size CNC machines are we talking about here and at what price point? I’m sure you realize CNC machines come in all shapes and sizes and prices (err… none of them are cheap though).

I’m thinking for most people it’s going to come down to at least 1 of 3 things (though each could have several aspects):

1. Precision
2. Repeatability
3. Time/material savings (maybe this is 2 things)

I’m in the process of ordering (waiting to get the okay from the other account holder) a small CNC and a 3D printer. This will make milling and producing smaller, high-precision parts easier (if you don’t like to tinker and troubleshoot though, you’re wasting your time with the “cheaper” machines).

-- "Well, at least we can still use it as firewood... maybe." - Doss

View Mainiac Matt 's profile

Mainiac Matt

4316 posts in 1048 days


#2 posted 08-20-2012 06:25 PM

We bought our first CNC at work to run a specific job…. headers used for large spools of film. They were made by sandwhiching 2x lumber between two outer layers of plywood and then routing a ‘U’ shape in one end. We ran hundreds of these with a set up that allowed the operator to switch back and forth between two stations…. where he would unload/clear/load one station, while the other station was cutting.

The second benefit we quickly realized was accuracy. We often run plywood parts used in packaging assemblies, such as crate decks, with slots for strapping and holes to bolt the product down. These holes had to match up perfectly to the customers product….. and a properly set up CNC doesn’t miss.

The third benefit was the ability to design parts with any type of crazy countour, without ever asking “how will the guys in the shop cut this”. In general, if you can imagine it, you can cut it.

We’re in an industrial, factory setting…. so space, power, air, etc… where all available.

Some years ago our owners bought a small Architectural Millwork company that speciallizes in retail store fronts, bank lobbies, etc… and I thought they would really make use of the CNC. But they had their ways of making cabinets and didn’t want/need to convert over to the production methods that are tailored for high volume cabinet manufacturing. So they infrequently use the machine to route some lettering in a sign, or to cut ADA logos into table tops, or for some higher volume store displays.

OBTW, if you use a good quality “compression” bit, and have your feeds and speeds set up correctly, you can route melomine all day long with almost no chip out on either to top or bottom edges.

-- Pine is fine, but Oak's no joke!

View David Kirtley's profile

David Kirtley

1281 posts in 1717 days


#3 posted 08-20-2012 07:46 PM

It really isn’t all that different. Just gives you another tool to make you more flexible. It doesn’t really add any capability that you can’t do with regular tooling but it does offer repeatability and free you to work on other things while it is cutting. It is also not an all or nothing proposition. You can mix and do some operation by CNC and others by manual machines or by hand.

Another thing to consider is whether you are talking about just making cuts like and saw would make router or are looking at 3D cutting. You can also get a 4-axis and 5-axis machines that can cut much more complex parts. A 4th axis is usually an option on a CNC router type machine but a 5-axis is a whole other world. The 4 axis would be able to do things like table legs and such with various shapes. It also raises the price for the CAM software to handle the other cutting.

The machines from Legacy Woodworking Machinery give you an idea of some flexibility. It is not a real plug and play operation. It takes some real learning and practice to get really complex things out of one.

-- Woodworking shouldn't cost a fortune: http://lowbudgetwoodworker.blogspot.com/

View Loren's profile (online now)

Loren

7808 posts in 2367 days


#4 posted 08-20-2012 08:17 PM

Well, I have a small vertical mill and I’m getting interested
in using machined aluminum parts in my designs so that’s part
of what I’m thinking about. For woodworking the mill’s
work envelope is restricted but I could use it to make
precision templates for overarm routing, for example.

I’m moving also towards cutting sheet goods on a vertical
saw I built (the saw is in its second iteration). In terms
of making a compromise between floor space and woodworking,
I may look into building a cnc with a 24”x72” work enveloped,
or thereabouts.

-- http://lawoodworking.com

View David Kirtley's profile

David Kirtley

1281 posts in 1717 days


#5 posted 08-20-2012 08:34 PM

Be sure to check out rawdawgs50 here on Lumberjocks. He is in the middle of one of the nicest home built CNC I have seen to date.

-- Woodworking shouldn't cost a fortune: http://lowbudgetwoodworker.blogspot.com/

View Mainiac Matt 's profile

Mainiac Matt

4316 posts in 1048 days


#6 posted 08-21-2012 01:17 AM

CNCzone.com is the most active forum I’ve seen for all thing CNC

-- Pine is fine, but Oak's no joke!

View dannelson's profile

dannelson

149 posts in 1091 days


#7 posted 08-26-2012 01:24 PM

I saw a nice used shop bot go for $3600 . The smallest id go for a machine is 48×96. we cut aluminum on our bot all the time as well as plastic , wood , brass, foam ect. as mentioned before you cannot beat a cnc for curved work whatso ever. We did a 92’ radius for a glass curtain wall for layout all plotted on 5×10 sheets of 3/4 ply that dog boned to together flawlessly try that with a swing jig. sounds like space is a factor for you. when we bought our cnc I was able to sell my panel saw. downsize my jointer and still get by with my small 15” planer. About the only bad thing that I can say about cnc is that you cant run them in a thunderstorm when the power is flickering. very bad things happen to what your cutting if you loose power for an instant. As for profit sources start dreaming, check out the VETRIC software we use vetric aspire and couldnt be happier.

-- nelson woodcrafters

View tyskkvinna's profile

tyskkvinna

1308 posts in 1706 days


#8 posted 08-26-2012 01:34 PM

I have found with CNC I can do a lot of tasks more accurately and depending on what it is, faster (sometimes, depending on what it is – slower).

For example, yesterday I used the CNC router to cut out shelving panels for a project the guys in engineering are making. They were 20”x20” with .568” holes spaced 1.2” off the edges with an 11.23×10.68” rectangular hole in the middle.

I COULD have cut these out by hand, using a router, a table saw and/or bandsaw and/or panelsaw, and a drill—but I made 18 of them yesterday and they were all exactly the same, and each piece took 2 minutes and 35 seconds to cut out (.75” ply)

Sometimes I make tabletops and they have a soft arc or curve somewhere. It makes it a lot easier to do.

As far as normal use that you’d likely use a single saw for—they’re basically the same. Wins and losses depending on the specifics and in the end they come up even.

CNC really shines when you get into a few specific areas:
-Repeating the same part over and over
-Cutting out a complicated shape very precisely
-Doing an otherwise dangerous cut
-Multi-step operations

You can get around the dangerous cut parts if you have a panel saw, but some of the funky cuts I do would be nerve-wracking if I did it on a router.

It does, however, require a completely different mindset from the operator and you can’t apply normal woodworking procedures to making something on the CNC. It’s just a different beast.

-- Lis - Michigan - http://www.missmooseart.com - https://www.etsy.com/people/lisbokt

View Jerry's profile

Jerry

2234 posts in 2266 days


#9 posted 08-26-2012 02:19 PM

I wish I could be of some help for you Loren, you typically offer me good advice in many of my topics. However, I have the same questions about a CNC with respect to what we do with custom cabinetry.

We are in our second full year of business and as far as I can tell we are averaging 2 jobs per month, with a few of them being larger scale. At this time we have 3 table saws, 2 RAS, 3 miter saws (2 are set up in shop)... I have a dado stack on a Unisaw and a 3 hp Dewalt RAS. We have a 24 tooth set on a PM66 and a 60 tooth on a TS3650.

We are only a 3 man shop, when we get buried I will typically hire another man or two.
I can cut out, dado and drill an entire job in approximately 10 hours, depending on size of job. My second guy can cut and assemble face frames for the average job in a couple of days. My wife (our 3rd person) can dovetail the average job in about 3 days, also depending on how many drawers.

My big clog in most jobs is after installation, time spent trimming out jobs on site, touch ups, etc… Applying finish is also a bit time consuming. Building doors another labor/time hog. Most of our jobs can be built and out the door inside of 5 – 6 days.

So I have also wondered how in our case the CNC would benefit us. I know the spenditure is 15,000 to 20,000 for a Bot, and upwards to maybe around 50,000 or higher for other CNC brands that would work for us. After much thought I believe a CNC would benefit us by:
1. cutting cabinet parts (all straight cuts)
2. Line bore shelf holes
3. dovetail drawer parts
4. slightly more accurate then I am (but I am fairly accurate)
5. Then obviously the rare curves we cut in our trade. In the past we have built 16’ curved receptionist desk.
6. Certainly repeatable cuts, our current job is for a laboratory, and we are building shelving units 6’ X 6’ with shelves adjustable every 4”. That job would have been great for a CNC. But then again, if we actually cut the job out too quick I might be faced with laying off my one good guy, and good help is hard to find. :)

So, my goal as we grow, maybe to the point where we do around 3-4 customers per month, will be to add a CNC. But the amount of customers we service will have to justify the CNC, which it does not at this time.

-- Jerry Nettrour, San Antonio, www.topqualitycabinets.net

View dannelson's profile

dannelson

149 posts in 1091 days


#10 posted 08-26-2012 02:49 PM

Jerry have you seen the bot for sale on the LJ forum ? cnc is not the answer for all .your times are not that bad for a complete kitchen. I average 17 minutes a sheet ,cut out, blind dado, toe kicks, strechers, shelf pins, pocket holes, dado for backs ,pilot holes for slides. on a 20 sheet kitchen its a little over 5.5 hrs including cabinet backs. I set up my cnc to dovetail the drawers on the end of the machine much like a leigh jig another 10 minutes per box cutting time . face frames very as per job . and I outsource my doors. cnc has allowed me not to get bigger but smarter as to how to compete with less labor cost and a higher profit margin. and we cut alot of other stuff besides just cabinets Dan Nelson

-- nelson woodcrafters

View tyskkvinna's profile

tyskkvinna

1308 posts in 1706 days


#11 posted 08-26-2012 10:28 PM

Jerry – I don’t think a CNC is what you’d want, at least not with the benefits you listed. You would be severely under-using the machine and I think it’d take a long time to make it worth the money.

Now, if you expanded what you did and branched it out – more extravagant cabinet shapes, for example. Carved cabinetry or historical matching, that kind of thing.

-- Lis - Michigan - http://www.missmooseart.com - https://www.etsy.com/people/lisbokt

View SteveMI's profile

SteveMI

867 posts in 2014 days


#12 posted 09-14-2012 02:57 AM

CNC shine when you need to make precision items and especially when you need to make a number of them. There is software out there that you just put the sheet goods on the CNC table and it can make all the carcass parts for a cabinet job.

One thing you need to understand is the “mindset” mentioned above. Remember that you are doing all your cutting with a rotary tool from one side of the material. Ideally you should be able to flip and cut features in the other side in perfect alignment, but that is a whole new ball game. Holding the material down whether vacuum, screws or hold down fixtures is one of the things that drive most CNC users nuts.

Earlier you said the real time problem you have is on-site and the CNC won’t help there unless the on-site labor is due to slightly off spec material from the shop.

I’ve had a smaller CNC for over 4 years and have found that many times it isn’t the best tool. Sometimes a simple router, the table saw or drill press can accomplish the task without the necessary setup. Many times I have designed the initial product in CAD, cut it with the CNC, refined the design and then used the normal shop equipment to make more.

If you intend to use the commercial cabinet software, that is fine. If you plan to make custom designs, then you need a CAD person on the payroll who understands what is needed to convert that to CNC friendly work.

Steve.

View Jerry's profile

Jerry

2234 posts in 2266 days


#13 posted 09-14-2012 04:00 AM

Thanks Steve, Lis and Dan for the input.

Cutting out a 20 sheet kitchen in 5 hours is pretty tempting :)

I geuss I can cut out the average kitchen in about 1 or 2 days, considering kitchens can range from 10 sheets to around close to 30 sheets on some larger jobs.

I have thought of the math involved. We only have one guy that we pay full time at this time. But let us say that a pay scale might be between 8.00 to maybe 16.00 per hour depending on different parts of the country. That could be any where from 1280.00 to 2560.00 per month for just one guy. Let’s say one guy at 1800 +/- and if the CNC could take that guy’s place, then there could be a significant savings.

But, there are so many things I or we do that really requires that extra help, such as on the job site. This past week as an example, we had some unconvential (stuff we rarely get into) work I needed to complete which was a minor overhaul of a RV camper. We demo 2 walls, removed water rot damage and rebuilt the walls. Removed flooring and rebuilt. We re sealed roof. We are welding a pole barn roof over the RV. Now we are building some minimal cabinets for the RV camper that is very simple. We did some plumbing, some minor electrical, getting ready to do some welding, etc… During the week I also needed to meet with 4 different customers (sales/planning/customer service), I had to make trips to the lumber yard / hardware. Without the guy who works with us it would have been very difficult to do this.

Then in the past month, the guy who works for us repaired our AC in the work truck. He removed the compressor clutch and cleaned it and made some adjustment that corrected whatever issue that caused the AC compressor to never engage. Personally I was just going to replace the AC compressor for 250.00 + as I did not know the clutch could have been repaired as it was. Then this past week he greased the chassis when we first heard squeeking in the ball joints, no more squeek.

And I know it probably sounds as if I am really bragging on the guy who works for me, and I am, but he is very good and good at a variety of tasks to include cabinet building. He came to us with no cabinet maker experience and just eager to learn and has learned quick. But these are some of the things I consider as I consider all of the pluses and negatives between paying labor versus CNC.

-- Jerry Nettrour, San Antonio, www.topqualitycabinets.net

View Doss's profile

Doss

779 posts in 984 days


#14 posted 09-14-2012 05:00 AM

You can’t always just think of it as buying a CNC to replace someone. Sometimes, buying a CNC gives someone a job and also expands what you can handle. You can now chase down more jobs knowing that you can set up a less experienced worker with the job of loading and unloading the CNC while the more experienced guys do the parts that humans do best.

Not to mention, it runs with little complaint and can do so for hours while you do other things (even if you don’t have a guy sitting around running it… just walk over and start a process while you go do something else).

-- "Well, at least we can still use it as firewood... maybe." - Doss

View oldnovice's profile

oldnovice

3845 posts in 2087 days


#15 posted 09-20-2012 07:51 AM

I am buying a CNC this week! So in four weeks, give or take a few days, I should be posting my first CNC project.

I think a tool like this can unlock creativity as it lets one spend more on the concept/design process.

Additionally I have some physical limitations when it comes to handling a 2.5 HP router for more than a few minutes and, routers are much noisier than a spindle.

I was planning to build a CNC but after 40+ years in design/automation/process control I wanted to skip that task and cut right to the heart of the matter, no pun intended, and start using one instead.

-- "I never met a board I didn't like!"

showing 1 through 15 of 20 replies

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com

Latest Projects | Latest Blog Entries | Latest Forum Topics

GardenTenders.com :: gardening showcase