It's Gonna be long

[denny]

I have a one man Face Frame construction cabinetry business and have been looking at adding a shopbot to machine my panels and also to do extra value added items to increase my revenue and have some questions on what is needed.

I currrently have KCDw, just the basic program without the cutlist and CNC options. So I need to know the best way to get from that point to the bot without spending money for anything that is not needed. It costs about 7 grand to upgrade to KCdW CNC or it is about a 500 dollar upgrade to get the cutlist feature. I also have a laptop with a 2.0 P4, 512 mb of ram and a 40gb HD

I also have a furniture maker who has asked if I would be willing to machine various parts like legs, tabletops and probably some embossed carvings for him so he can just assemble them along with a request from another person to machine 4x8 acrylic sheet stock into sides for acrylic tanks. That will take a different program than KCDw. Any suggestions on something that would be a good one?

Also, what would be a recommended setup for this type of work.I am not sure if it would be an advantage to step up to the newer faster version or whether I could do just fine with one of the older style bots.If I had a 4x8 sheet of plywood and needed to cut 6 base cabinet sides that measured 22 3/4 w x 30 h and ran a 3/4"wide x 1/4" deep dado along the bottom and top for the shelves, approximately how long would it take on one vs the other?( I have a line boring machine so I wouldn't have to have the bot machine them, that could be done by me while the bot was machining another panel. Are the bots good at machining acrylic sheets without burning? The furniture parts would have to be drawn on a program and saved so I could call them back up and run them when an order was placed.

I also would want the factory table and factory machine setup. IMO for me it is better to get a machine up and running as soon as possible so I can keep working and keep the money coming in.How is dust collection done? Is it a standard feature or an option? Also, how are the pieces held on the table? Do I need a vacuum device to hold the pieces from moving around the table?

I think that is all for now. I am sure there will be more LOL

Denny

[elcruisr]

Hi Denny,
We build custom and semi production furniture for a niche market and do all our panel processing on our 'bot. We have also built a considerable amount of outside work as well, it's become over half our business! Without the 'bot we wouldn't be where we are today.

That being said there are sort of two directions you can go. You could go with either a new Alphastep machine or used PRT with a router head for cutting or go with an Alpha and a spindle. With the router if you get into serious production numbers you are going to get very adept at rebuilding the router head. With the spindle you will be able to handle faster production and rebuild every few years or so if you take care of it. The spindle is quieter, much more powerful and has much less runout which means cleaner work in plastics and tighter tolerances. The downside is they ain't cheap! We run an Alpha machine with a 5 hp spindle.

As for speed differences my PRT ran through .75" plywood at about 2.8"/sec my Alpha does it at 10"/sec. I've handled acrylic up to 1.25" and polycarbonate up to .75". I've also handled solid wood up to 1.5" and do alot of 1.125" particle board for table tops.

We have done some carving for people but there are people here who have done alot more carving than I will ever do!

Think big vacuum if you are going to want to do serious production numbers. We started with a 7 hp blower and quickly went to a 15 hp FPZ blower. We are now looking at a Becker stacked pump for even more vacuum. You'll want all you can afford when you start chopping up warped sheets of ply at 10"/sec.

Dust collection you provide and hook up to their collection hood or you can fabricate your own, many of us start with the factories and when it finally dies we build our own. We use a stand alone Jet dust collector, pretty much anything meant for the job should work.

If your software can export .dxf or .dwg files of the parts you may be able to get by with the software included with the machine. If you want to do carving and sign work you might need to upgrade. We use ArtCAM Insignia and it pretty much meets our needs, others use different software with good results as well. Figure out exactly what you want to do and then tell the software folks you want to see it done before you buy!

Do lots of homework and ask lots of questions, be ready for a steep initial learning curve. The more you know before it hits the floor the better! Find out all you can about different cutting tools and how they sould be used, CNC tooling is a different world from the router bit world and the choices will effect your work. That said after 20 years as a traditional wood worker I'd sure hate to be without my 'bot!

Eric Lamoray

[ron brown]

Denny,

The learning curve on CNC cutting can be steep. I agree with most of what Eric states. And, do use software before you buy.

Simple furniture parts are. Intricate parts may take a lot of time and waste a bit of material before one learns how to make them. Again,as Eric implies, this is not standard cabinet shop thinking. Cutting and indexing is on a different type of platform and thinking.

Good Luck,
Ron

[richards]

Eric and Ron gave good advice. Let me add a few comments. Get the Alpha, even if you use a Porter-Cable router head, like I do. The jog speeds alone make a tremendous difference in total cutting time.

Pay close attention to what Eric said about using a spindle instead of a router. The Porter-Cable router, although adequate at lower feed speeds, will not allow you to reach the Alpha's full potential. I'm upgrading to a 5hp spindle as soon as I move to a shop with adequate power to run everything.

I haven't been able to find the right feed speed/router speed to get a one-pass cut that I'm satisfied with, regardless of cutter size and material, so, I cut the first pass 0.025 - 0.040 inch oversize at a modest speed, usually 3-4 inch per second, which is all that the Porter-Cable can handle without bogging down too much, and then I make the final pass at 8-12 inch per second. The Alpha can easily handle those speeds.

As far as a vacuum system goes, I've had to make do with a Fien vacuum and a 3/4-hp Gast vacuum pump, again because of inadequate power in my shop. The Fien vacuum and a vacuum mask, custom cut for each sheet of material, works fairly good. Using 1/2-inch MDF for the vacuum masks (about $15 per mask) gives a mask that can be re-used without breaking under its own weight. Spraying a little adhesive or using a little rubber cement on the mask helps keep parts from moving. Leaving 0.035 inch of material on the first heavy-pass also helps, requiring a fairly light-pass on the final cut, which normally doesn't push the material enough to break the vacuum. Depending on the material, the Fien vacuum works best when the cut pieces are at least 1 foot square. On smaller pieces, I leave about 0.030 inch of material that is easily cut through with a laminate trimmer.

The Gast vacuum pump (and the Rousseau pump that works off a compressor) are great for smaller parts. I use pods made from MDF, coated several times with Shelac, to allow them to hold vacuum, and from polyethelyne (spelling?). The Gast pump requires making pods and using gasketing material (closed cell foam), but it works very well when cutting smaller parts.

As far as costs go, the Fien vacuum cost about $300. Materials to make a four-zone vacuum pad, using the 4-zone Shopbot file, adds another $200 or so. The Gast pump cost about $500, and the piping, tubing, fittings, etc. cost another $400. Neither the Fien vacuum or the Gast vacuum pump are my first choice, but they work reasonably well and require little power.

Ron said that "the learning curve on CNC cutting can be steep". As far as I'm conserned, he greatly understated the learning curve. Not only can it be steep, but it WILL be steep. Even though I've been programming process control computers since 1975, I've spent 90% of my time since getting my Alpha in July, messing with software, instead of cutting material. The PartWizard program, that comes with the Shopbot does a very good job of converting DXF files to tool paths; however, to get any useful life from your cutters and any efficiency from the machine, you'll need to learn to tweak the files. I always change the start point so that I can ramp into a cut. Check your router bits. Few of mine are built to plunge into the material. It's easy to see: if the cutting edge on the end covers at least 50% of the diameter, the bit can probably be plunged into the cut. Almost all of the bits that I have have a cutting edge on the end that is less than 50% of the diameter, meaning that they *must* be ramped into the cut. Ramping into a cut and step-drilling have to be added manually to the PartWizard *.sbp files. It isn't hard, but it takes time to learn. For instance, two J3 commands in a row, in the PartWizard generated file, usually signals the transition between two parts, meaning that it's time to add a ramp routine.

One last thought: Since installing the Shopbot, I haven't used my UniSaw once, partly because it is almost buried, but also because the Shopbot has made it unnecessary. The same can be said for the shaper, the radial arm saw, and the twenty-odd routers that I've accumulated over the years.

Mike

[elcruisr]

Hey mike I like what you said about your unisaw. I've got a HolzHer panel saw that I was mighty proud of before we got our 'bot. It's now for sale, anyone interested?

A good point to about ramping entries and step drilling. That's one of the reasons we went to Insignia. We can do straight or curved lead ins, with or without ramps and tabbing with complete control over all the variables with ease. We do alot of sheets of parts nests and it really helps.

Denny, if you can get a chance, a trip to a Shopbot camp or the Jamboree will pay off in spades. There's tons of information at these events and it's nice to hear how other 'bot owners are doing things and trade ideas.

Eric

[ron brown]

"it's nice to hear how other 'bot owners are doing things and trade ideas."

Almost as important as hearing how NOT to do certain things.

Ron

[denny]

Thanks for the input everyone.I agree with the idea of visiting a shop that has one, and in fact that is what I am trying to set up with this thread. Hopefully I can get a good idea of the machine I will need and then find someone who has the same setup or close to it that I can visit and judge for myself if it looks like the way to go. I have bought equipment in the past without doing enugh homework and then came to regret it, so on an item like this one I am going to make sure that I am as familiar as is possible before making a decision.

Does anyone have any pictures of their vacuum setup? I am still not sure how the different types work, Are there different types of tables with holes in them like a downdraft sanding table? and will I need to change how it is setup when going from 4x8 sheets to smaller parts like window valances?

[richards]

There have been lots of posts on vacuum systems in the forum. Doing a search on 'vacuum' will get you started. Some of the posts have photos.

Software supplied with the Alpha includes a 4-zone vacuum table top, which I used for my machine. All of the plumbing is 2-1/2 PVC pipe from the local Home Depot. Since there are 4 zones, I installed a shutoff valve to each zone to control air flow. Also, I keep several 24x48 inch MDF sheets (1/4-inch thick) to mask off various portions of the table, and even portions of the active zone for those times when I use less than 24x48 inch material. Even with unused zones turned off and masking material closing off unused parts of the active zone, there can still be substantial air flow - vacuum loss - between the material being cut and the 1/4-inch MDF. For those times, I simply tape the gap with 1-inch wide blue masking tape. It comes off easily and seals well enough that the air leaks are blocked.

Smaller parts require the Gast pump. In any case, I try to have at least 80 - 100 lbs of atmospheric pressure on the material being cut. With the Gast pump, that means the piece being cut only needs to be about 4x5 inches while the Fien only holds pieces to about 12x12. A lot depends on the surface texture of the material being cut, the amount of dust trapped between the table/pod and the material being cut, and whether or not a piece of sandpaper or spots of glue have been added to the table to get a little more grip.

One last comment on vacuum hold down. I started by screwing everything to spoil board. It works very well, but finding a spot to place a screw can get difficult when you have a 20-30 sheet run and each sheet is optimized with little waste. There is also the problem with bowed and warped material. After messing with screws for about 2-3 weeks, I stripped the table down to bare metal, installed new material and started with the Fien vacuum. It has worked better than expected.

Also, I believe Eric mentioned in one of his posts that you should consider the Shopbot, the vacuum and the spindle/router to be a system. The Alpha with a router instead of a spindle works, but not as good as it could with a spindle. An Alpha and a spindle without a powerful vacuum will not hold the material tight enough to allow the cuts that the spindle is capable of making. And of course, even with the fastest Shopbot, the 5-hp spindle and the biggest vacuum, an inferior bit/cutter can negate everything else - and all of that assumes that you've created a proper tool path that lets your 'system' work to it's fullest potential.

Going from traditional tools to a CNC router requires a different mind-set and some significant thinking time to reorient yourself to the possibilities of CNC routing.

Mike

[elcruisr]

Denny, most vacuum tables will be controlled by valves that open/close the different zones on the table. We have a 12' table so we use 6 zones 2' long across the width of the table. The table is topped with a mdf ( or in my case ldf ) "spoilboard" which is porous enough to pull vacuum through. We typically use 1/2". As you cut parts you will eventually either start plugging up the pores or leave enough shallow grooves in it that you will start loosing good holding and dress it down smooth again. This can be done many times untill the spoilboard gets replaced.

You can increase vacuum by various masking / covering techniques or by upping the pump horsepower. Another aproach is to use vacuum "pucks" on the table but this is often times more geared to solid wood parts or smaller repetitive parts.

Bear in mind that increased production speeds will need increased holding power. That's what we discovered the hard way.
Our primary business with our 'bot is production routing. We make parts by the hundreds, thousands and sometimes ten thousands. That means we need lots of holding power and no time to mess with lot's of tricks to make less powerfull systems work. This, of course, costs some money but pays off for a business like ours. There are probably dozens of ways that you can approach holdown systems but your options begin to narrow down the more production speed you want.

It's very important to decide what your expectations and plans for the machine are going to be in your business and then find out what your options are in the initial setup. This will save alot of headaches during the learning curve. If you can say I want to be able to import .zxy files from Artoscrad and produce 200 left handed reverse double widgets a day in 120" thick ironwood and be able to cut unobtanium for outside shops on the side then the folks who setup and sell these things will have a better idea of which way to steer you. It's also nice to be able to find shops who are doing exactly what your defined goals are and then hearing what has and has not worked for them. A vague idea will get a wide variety of "how to do it's" which may not even apply to your goals from people who approach CNC work for very different jobs! Do lots of homework and ask away as you narrow down your choices and you won't regret it!

Eric