Vertical Table Router / Mill

[harryn]

Hi

I am still very new at this, so we will see where it all goes. It will certainly take time.

I thought I would start by discussing:
- What kind of tooling I own today
- Current general accuracy / precision capabilities
- Improved precision / accuracy goals
- What kinds of things I have built / hope to build
- Location available to put the unit
- ideas on construction of the unit
- Running parts list (for my own sanity)

Wow - already looks like a big project just to type it up.

[harryn]

Current Tooling, Capability, and Location to put unit

CAD
- I know a number of people who have used CAD, but I have never used it.
- This project is partially to force me to learn CAD (for hobby use)
- All drawings in the past have been with a T squre and pencil (yes, I know)
- Actually, I am not completely computer inept. I have done some drawings using excel drawing functions - and it is quite a pita, but works.

G Code
- Guess what, I don't know that either

Office
- Yes, I can type

Mill (large ) - occasionally access, but rare.
- My brother has a Bridgeport Mill clone manual with about 0.007 backlash screw drive (not ball screws)
- He was trained as a machinist in OH, and is pretty good, but - too busy to do my projects regularly, and lives too far away to have ready access. ( I live in CA)
- I have watched him do just enough to know how careful he is, and how sloppy I am.
- It took him many years and lots of $s to accumulate all of the tooling needed to be the perfect generalist. Of course, it takes him 4 hours to drill the first hole, but it is a dang nice hole.

Mill (small)
- A friend of mine has a HF small mill
- No offense, but between its quirks and mine, nothing useful happens
- By the time I actually make a few good cuts, I get too ansy to keep doing more good cuts.

Lathe
- Same friend has a HF lathe
- Same comments

Router
- I have a nice Bosch VS router
- It is probably the nicest tool I own

Circular Saw
- I have 2 decent ones
- One for left hand work, one for right hand work
- If you think that is funny, so does my wife, but it is so handy
- I am not an expert, but can make reasonably decent cuts 50 % of the time using an Al angle guide clamped to plywood sheet

Cut off saw
- Wood cut off saw
- Really a power miter box I guess
- Decent, not perfect angles with its wiggles, etc., but ok for molding use if you finish up by hand

Drill
- Battery powered drill
- AC powered drill
- both are 1/2 inch decent, not industrial drills.

Metrology
- Decent callipers good for approx 0.002 inches (when I use it)

After that, we are down to hand tools like hammers, hand saws, sander, screwdriver, etc.

Items not owned
- Almost anything that can accurately cut Al
- Welding equipment
- Table saw, radial arm saw, drill press, etc.

Obviously, the design needs to be one that can use mostly parts which can be purchased. I can do a few touch ups here and there, but it will be limited.

Location to Put Unit
- I don't have a basement, and the garage is largely full
- I have a place in mind in the garage that is approx 30 in x 30 in x 7 ft high
- This needs to hold everything assocated with this unit
- Roll around wheels are a must
- One nice thing about this size, is that it will fit in the back of the Dodge minivan

Enclosure
- I really want my kids to be able to use this thing to build projects, so safety is a big deal
- Dust and noise are big deals also, so an integrated enclosure is a must

Existing Accuracy
- I am not that patient, so precision and accuracy both suffer
- I find I can drill 2 holes well. If I make 10 holes, at least 2 of them are pretty mediocre.
- Realistically, holding better than +/- 1.0 - 5.0 mm isn't that easy for me on most projects, especially as I get tired and the kids start asking me questions.

Improvement Goal
- I see my projects fall into two catagories
- About 2 x 2 x 12 in or smaller in Al
- Things done on plywood sheet

- For the small Al projects, it would be nice to hit +/- 0.1mm or less consistently. I can handle a bit more, but that is really what I would like to do. Interestingly, it just has to be precise for that single run, and short distance.

Almost all of my work is now in 7050 or 7075 Al, as it machines so well, and has good mechanical properties. (and scrap is available)

- For the sheet plywood projects, +/- 1.0 mm would be great, over a 24 x 20 in. distance. I have already given up on being able to load an entire sheet in the unit, and am going for rough cut 24 in tall sections.

Not mentioned yet, but important. My wife uses the power miter box as a moulding cut off saw sometimes. I just cringe that she will hurt herself on it when I am at work, so it would be nice to be able to have her really like using this cnc router without a lot of learning curve for simple moulding cuts.

[harryn]

Examples of Projects

- Projects from the past
- Shade Trellace picture and commentary
- Custom Flashlight parts
- PCB

Yes, I am one of those crazy flashlight hobby guys who spend way too much money on silly little lights.

[harryn]

Ideas for Construction / plans

The basic idea I have is to end up with something that looks like a refrigerator.
- The "back" of the refrigerator is where the wood / Al is mounted.
- The parts are loaded in from a slit in the side
- All parts get mounted on a "cutting board before going into the router
- The cutting board goes in to the router up to a "stop" index point and the vacuum hold down holds things still. (at least in theory)

- If cutting sheet, the plywood would be mounted similar to the way a lumber yard mounts plywood for rough cutting (vertical, 4 ft high)
- The piece would slide into a "slit" into the router riding on a rail and come to a pre-set stop
- Possibly a vacuum hold down to pull it back flat against one wall
- The X axis would be vertical, the Y axis horizontal, and the Z axis (plunging) would be horizontal into the board.
- The X axis rails would mount on two walls of the enclosure

Nominal size cutting area (inches)
- 24 ish high (X)
- 15 ish wide (Y)
- Able to drill a one inch hole through a 6 x 6 post (Z)

Longer term items to plan for
- 4th axis rotary for use as a sort of lathe cutter / round objects
- Ability to rotate router from facing wall to facing "up" for long drilling projects (such as a 250mm deep x 20mm dia hole for a flashlight I want to build)

Rails
- I have looked mostly through the pacific-bearings catalog for ideas (they seem to have most everything)
- I am thinking of using these metric redi-rails for all 3 axis (cannot get link to work right now)

Drive
- Belt drive on all axis - something like this http://www.brecoflex.com/?CATID=1&SC...ENID=1&TBGID=5

- Stepper motors - thinking of these or similar to make the wiring easy - http://www.imshome.com/mdrive42ac_plus.html


Enclosure / Frame
- More or less trying to go for a "unibody construction" approach
- I am not an MDF fan at all, despite its interesting capabilities
- Will probably make this initially from 3/4 or 1 in plywood walls with 2 x 4 framing
- If the basic idea works, and I am bored, it might get converted to honeycomb walls like these. http://www.pacificpanels.com/ They are quite stiff.


Router (existing)
- Bosch 1617 EVS 1/2 in variable speed router
- Existing

Spindle
- Hope to use the router for the cutting without a separate spindle
- Have not really thought through mounting the router yet
- It uses a 1/2 in collet, so that sort of sets the basic limits

Software
- There are the usual suspects of course
- I am keeping an eye on this guy http://gcam.js.cx/index.php/Main_Page
- What I would really like to do, is find someone in the SF Bay area who is building something, and go help them (be their student)

[harryn]

Running Parts List

- Here I am hoping to regularly update the parts list for the project in case it helps anyone else with a build.

- Feel free to suggest alternatives and places to get items.


5 each 3/4 Plywood A/B 4x8 sheet $ 35 each = $ 175
(home depot)

10 each 2 x 4 x 8 ft kiln dried $ 3 each = $ 30


Might replace some of the 2x4s with 80/20 or similar rail


8 each RR65U carriges $ 163 each = $1,304
(Pacific Bearing price)
Might need 16 of these to do it properly

Rail
0.27 /mm + $ 20 cut charge per order

4 each RR65 rail x 1200mm $ 324 each = $ 2,592
2 each RR65 rail x 615mm $ 166 each = $ 332
2 each RR65 rail x 300mm $ 81 each = $ 162
cut charge $ 20


Belts
1 each 50 meter roll of AT 10 precision fit belt
- Nylon backing
- est 100mm wide
- Target supplier - Beccoflex


Belt drive hardware
- Target supplier - Beccoflex


Stepper motors
- Target supplier - IMS ( www.imshome.com )
- 34 or 42 size AC driven stepper motors with power supply and drivers built in


Constant Force Springs to counter the est. 50 Kg / 100 Lb gantry weight
- 4 each x est. $ 25 each = $ 100.
- McMaster- Carr


Spindle and mounting
- 40 taper
- tooling to go with it
- ( I had not really thought about this part before. Lots to learn)

Drivers

Computer


Software


Wire


More I am sure

[ger21]

Ambitious project.

Fwiw, it's much easier to cut moldings on miter saw than with a router. A router will almost always tear out one side of the cut.

[harryn]

Originally Posted by ger21 Ambitious project. Fwiw, it's much easier to cut moldings on miter saw than with a router. A router will almost always tear out one side of the cut.

Thanks for that very good point about a router vs miter saw.

Actually, I won't go forward with the project if it gets toooo challenging. - especially if it starts to look like that amazing kitchen you have taken on.

(I have a project that is going on 12 years now BTW, and my wife won't let me actually start building this one till it is finished)

[harryn]

Hi - I started to do the calculations for the mill project.

From others on the forums, a common gantry weight seems to be in the 50 Kg / 100 lb range. Originally I thought this was a lot, but after adding it up, this actually seems pretty close.

Since my gantry for this unit rises vertically for the first axis, essentially the entire weight of the gantry is lifted by the stepper motor / belt drive on the way "up", but wants to pull the whole thing fast on the way "down".

Lifting 100 Lbs with a stepper motor is not that hard with the right setup, but the great change going up /down seems like it could cause problems.

Is the usual method to counter weight large masses that need to go vertical ? Is this really needed, or just a good idea ?

Thanks

HarryN


Note - question answered in the linear motion thread - so far, plan to use constant force coil springs from McMaster Carr

[harryn]

Hi

Not really a lot new here - still working on a parts list / budget plan. For some reason, I could not edit my older parts list, so this is an add -on list.

The previously chosen rail method is just too expensive for my budget. I am now thinking about using structural Al or steel and slippery plastic as the bearing material.

Misc info collected today

Vespel S 211
- This is a very high performance polyimide filled with graphite and teflon
- Possibly the ideal material for a plastic bearing except for price
- Price - turns out, it is pretty much the most expensive as well
- US Distributor info - http://www.curbellplastics.com/vespel/

Price - hang onto your hat 10 in x 10 in x 1/8in plate = $ 1700 each. For the metric people, that is approx 250 x 250 x <2mm thick= Euro 200 +. Even in Euros it is expensive.

This is not the path to economy bearings, but for the pros, an amazing material


UHMW PE (ultra high molecular weight poly ethylene)
- Nearly the same coefficient of friction as PTFE (teflon block)
- Very high impact resistance
- Very hard to bond to, so that will be exciting
- Very wear resistant when run against steel, etc - better than most materials
- Still has PTFE cold flow / creep, so the design needs to deal with this
- chemically nearly inert
- Definitely cheaper - see link to an on - line store I found. Less than $ 100 of material will probably be enough for the entire project.
- This is probably a reasonable path, and cheap enough to proto with.

http://www.k-mac-plastics.net/uhmwpe...-bar-stock.htm

Delrin / Acetal
- need to look at this some more, but it probably would work as well
- Coefficient of friction tends to be a little bit higher

[harryn]

Hi - latest parts list update - stepper motors.

I picked these ( www.imshome.com ) because they have they take in AC directly, and include the power supply and driver built into the stepper motor. They are available in 34 and 42 size only at this point.

I always mess up wiring, and this seemed like a way to make my life easier. As you can see, not exactly cheap, but maybe this is just reality.

There is also a version listed below which includes the controller built into the motor assy as well (single axis control). (the more expensive list). This is from a west coast distributor powermatic.net which is only a few miles from me.

MDrive 34 Controller Version with AC Input:

MDI3MRQ34A1 $750.00

MDrive 34 Drive Only Version with AC Input:

MDM1MSZ34A1 $642.00

MDrive 42 Controller Version with AC Input:

MDI3MRQ42A1 $995.00

MDrive 42 Drive Only Version with AC Input:

MDM1MSZ42A1 $833.00

Anyone have any comments on the pricing of a power supply plus driver plus 32 size stepper motor for comparison ?

3 motors minimum x almost $ 700 / each = $ 2,100.

Sure adds up.

[ger21]

Good quality (Vexta) 400 oz motor = $140
Gecko G203 Vampire (can't be killed) = $147
3 of each = $861
Another $400 should get you a good breakout board and power supply.

[ckm]

I have steppers from Keling. They are pretty cheap and work great.

You can get pretty high powered versions in the 34 and 42 frame sizes from around 400 oz. in. to over 2000 oz. in., the largest ones are $280.

They also have servos, which are also cheap-ish. Their servos are $100-$150.

I use a HobbyCNC board, but Geckos are indestructible. You should also look at Xylotex, as they have complete kits, although they are not as high-powered as the Keling ones.

Chris.