JP Warnke published a new build:

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Hey Star. 45 Series Minitec. Im not sure what the cost comparison is for 8020 (i used to use them all the time ...i think i have a pdf of their per unit profile costs actually if someone wants one; though its a few years old). I've been using minitec at work lately though; and i had the profiles loaded in my CAD library already; hence minitec!

It will hopefully be rock solid. I know using linear rails and ball screws gets pricey (not to mention the cost of materials; as we will have steel fabs and alum tooling plate in some areas); but we really wanted to invest in building something great that will last, that will be fun to machine with and that will make nice clear smooth cuts. The risky side is - not having done this before - we risk missing the mark in some areas (which could get even pricier!). Even though we both have machining/cnc/design experience there are some items here we def need to do a lot of reading on now to make our money count!

 

Thats good to know on the ball screws. I figured these things would be strong. I have seen other dual drive machines with 5/8" ball screws, so i figure not really any difference between these and 16mm.

We were concerned about that the motors as well though. We are now thinking we might go up to 34s.

I did like a lot of the stuff on cncrouterparts. We had actually been originally considering getting the nema23 4-axis plug & play setup from them, but we recently changed course and began looking at building up our own controls. My pappy has worked up a rough list of goodies we are thinking about (from automationtechnologiesinc.com):

- (5) NEMA 34 640 oz-in Stepper motors (KL34H280-45-8A)
- (5) KL-5056D Digital Bipolar Stepper Motor Drivers - 32 bit DSP based
- (6) Motor cable connectors
- (1) Handwheel MPG (wireless) for Mach 3 controller, 4-axis (X, Y, Z, A)
- (1) Water Pump 200 GPH for spindle cooling system
- (1) 2200w 3HP Water cooled CNC Milling Spindle,KL-2200
- (1) 2.2Kw (3HP) VFD for Spindle (KL-VFD11) 110VAC input, Connect R and T
- (1) Unregulated linear 960W/48 VDC/20A Toroidal PSU (KL-4820) with 5VDC
- (1) CNC 6-Axis interface breakout board with relay and spindle control
- (1) 24V 2A Switch power supply.

 

Thanks Flo

On budget - if we can save and spend less; then Im definitely all for that! If you're saying you think we will go way over that, then..... : (!!! In our case we have access to machine shop and machine shop tools; i have connections to controls engineers for help, good water jet & fab vendors, etc. Much of the machining we will do ourselves (minus jetting), so cost-wise we are ok there. It's mostly just going to be paying for raw materials, fasteners, electronics, etc. with about 250-$300 of water jet work. 5-7k is really the budget cap range. If we can do this thing, work out the bugs and make it function the way we want for less than 5, then ill be thrilled.

On answers to my ?s:

1) - Wow...thats a weird thought! 90x180 seemed so strong already! Minitec doesnt make a larger one X-{ So...if we went with the L/wood setup you're suggesting - is it like an L-bracket hanging off the top with a solid piece of soft wood like pine against the backside of the extrusion? Would sandwiching thin rubber/urethane or foam inbetween the extrusion and a piece of soft wood help any further? I just really don't want chatter on cuts to be an issue at all. Makes me wonder if i shouldn't try for a 4' width X-(!

2) - When you say 'couple' two axes? Im not understanding? I do have motor couplers on each side of y ball screws (is that what is meant here?). Do i need also to somehow tie these sides together underneath with a crossbar or pulley setup (like i've seen done on smaller cncs with a single Y-drive motor in the center)? If i can avoid that id prefer to; but if i have to redesign to tie across from bracket to bracket, id rather do that than deal with major racking issues later on.

3/4) - Good to know on the ball screws. So you're saying it might not be best to move up to NEMA 34s for this machine? But to go for lengthier 23s? Right now we have 420 oz-in 23s. If we went up to 640 oz-in Nema 34s though with the 16mm ball screws, this would be better, yes?

5) Well...i don't absolutely need the 12" I guess; but the big hope with it was the ability to use a rotary axis (we may be receiving a 10" ish tall rotary axis from someone; so if i can find a way to use it on this machine; that'd be awesome. It's not a necessity, but it'd be really cool if i could make it work). Because of the height on that rotary, we were thinking (man...it'd be cool to do some artwork on 10-11" ish rounds on a rotary if possible). Im new to a lot of this; so im probably being a hopeless dreamer; and i will probably have to learn the hard way <: ), but if there is a way to accomplish the height and maintain the rigidity, i'd love to be able to pull it off. If it's asking for trouble and enough people tell me "nOOOOOOO!!! Don't do it!!!!" Then Ill def listen X-)

I did change my z around some this evening also anticipating it would be better to spread the rails though (although i did not go opp sides - think it would be better to do it that way or better to spread the load top and front as i have here??):




6) Thanks. I will need to read up some more on this stuff still.

As far as the machine bed - there were some items i did not show before that might help some more?? :

here is the full machine pic at present:





I have front/rear water jetted 1/4" steel plates with a bunch of holes into my sandwiched profile stack. The profiles arent 90x90s, but the table top is 19mm thk over a 45mm thick (45x90 pc) over another 45x90 pc (at least on front and back), . The side pcs shown are 45x135s. I will be gussetting it like crazy underneath to try to I will probably consider going to 90x90s though around the base though. If i can't cut thin sheet steel with this, it's ok. I didn't count on it (just would have been a cool perk).

Anyhow, thanks so much for input!

-JP

 

2) So here is a video of the P3 Cobra I found in action: Looks like just one central stepper pulleyed to 2 ballscrews on either side. Seems like that would definitely get rid of any racking problems; but i guess then im wondering - I've seen other people build these without a crossbar on the underside, and with the dual steppers as i have - for example:


Maybe these designs typically less dependable for heavier gantries like the one im making though?

I may rework my design to use a tie bar. I'd rather not if there is a way to make it function well without tying it across underneath; but if other builders like yourself really think it would be best; ill probably pursue a redesign there.

5) I totally agree. I am working up some strengthening gussets on the back side of the floppy spindle plate.

6) Ill check into bosch and 8020 (have used both before) but i know minitec has a good product as well. Ill select something about that size that is the most rigid (and straight/flat).

Thanks!

-JP

 

Whoa : |. ......take it easy....

I'm not rejecting denying or even questioning any of your good advice. I'm just trying to understand the reasons for doing something one way or another and what you mean by what you say in some cases (and it sounds like you werent reading what I had written or understanding what I meant in a few areas as well; that's ok - it happens).

I AM a machine designer and I certainly don't claim to be a genius but I fair well enough to provide for my little family. I try my best. I was not provided with money for a great education so I've had to work and read in my spare time to learn as best I can. Matter of fact the money my father and I have for this is only due to his business sale (and again I plan on saving as much as possible; it's just we have budgeted for 5-7k maximum). There is no need to look down on someone else who doesn't know something you may know, right?


Anyway; Nobody can know everything. I won't berate you for your English if you don't berate me for not understanding building CNCs as well as you do. fair enough? : )

I'm just here to learn. I haven't ordered anything yet (except my ball screws). I fully confess I may be shooting for the moon with my z height - but I'll remind you that I'm not fixed on doing it exactly this way; that's why I'm asking for advice - and I do appreciate your advice and I certainly have been considering it (if I did not give you that impression I can promise that was not my intention).

Anyhow, thanks again.

Best regards

-JP

 

Thanks Star. That'd be helpful.

Do you think because of the height and width on my gantry i may want to consider a tie bar anyway? (I got the impression Flo was thinking it would be necessary in this case?). I just know I've seen other 4' gantry spreads that don't tie together at the base; and I'm wondering if they still work well. Seems to me like your motors are the same you can set one up and just sort of loose the coupler on the other to get it in tune?

 

So on the Ys you're thinking don't tie them together? Or do? Guess I'm confused because in the P3 cobra vid here they are tied across the bottom with a plate. Are you saying 'p3 model is a good one to mimic in terms of the Y-action/y-motors/ballscrews'? Or you think that whil it's good, the dual ballscrews/dual motors setup I have on Y right now will be still be good and that I just need to bring my gantry down a few inches and get the spindle mounting less floppy?).

I'm thinking that's how I'll move forward here; I'll take my gantry down a few inches; shorten the Z ball screw and gusset my spindle plate to keep it from swinging like your grandfathers clock pendulum : ). If I lose the ability to mount a rotary I guess that ok.

I'll just not cut steel with this. I think that much is clear at this point X-}. No steel. Alum though?; id def like to handle aluminum on occasion.

I think I'll go to nema 34 640 oz in for the Ys (and X) instead of the 23 420 oz in ones I have currently. Unless it really is better to use longer nema 23s? I guess I don't understand the advantage of a long 23 over a short 34 of the 34 still has a higher torque rating? Would the motor windings along the longer axis in the 23s help with control/accuracy maybe?

Thanks!

 

Thanks for all the input! I've reworked this thing; shortened it up 4" and up-sized the motors to those 34s. I still need to work out my Z bracketry and do a bunch of tedious fixes and what not; but it's getting there bit by bit.

I definitely feel better about the height drop. I think I will still be able to find a way to mount the rotary actuator off this as well (its 12" tall, but I will probably build a sub-plate that can hang off my table to set the rotary on and get the axis down further. It's not a central desire to get the rotary working, but I'm satisfied with this idea; If I can still get 7 or 8" dia. work pieces on a rotary with this, that'd be awesome.

 

Thanks! I will try to remember to post a build list when I get this thing all worked out!

I did find out my father ordered 5mm pitch for these ball screws instead of the 10mm ones. I guess that's ok. It will be better for control, just slower travel. I'm casually considering moving up a bit yet on my motor length because of this.

...Think I'll stick with the 34, 640ozin ones for now; but if I'm dissatisfied later it I can switch them out.

right now I'm just working in a bunch of the details. Fit spacers all over the place and hole patterns and detail prints and getting quoting on a few things.

I had a water jet vendor my co. uses give me a ballpark of about 250-300 to jet my end pieces and all 20-30 so fit spacers out of a 1/4" pc of 1020. I was ok with that; although I'm thinking I'll see how much it would increase if they jetted the clearance holes out as well. I'm guessing it will double : |.

I'll try to post some machine Pic updates in a few days.

Best Regards,

-JP

 

Hey Star. Yep. Design is pretty much done. We received our linear rails the other day (they looked good). I've got my extruded alum being quoted right now. The bulk of my other details will be jetted or plasma or laser cut. Getting quotes on those.

I'm detailing everything right now. Hoping to start cutting parts within a few weeks (lot of it depends on our jet/plasma/laser vendor. Those guys are always swamped and I don't want to pay the higher premium for faster delivery. I'm ok to wait.)

Hopefully I can start posting some build pics within a month or 2 here!

 

And we just cut an order for the minitec and another order to laser cut most of the steel pieces for this.

That will comprise a lot of the pieces/items seen in the pics here.

Good progress being made.

 

Most of my mechanical items are on order. I have a fasteners list and maybe about 5 plate details i will need to get some stock for; other than that i have just about everything else on its way....minus controls

To be honest; this is a daunting area....we only know enough controls-wise to be dangerous (like...not in a good way, hah). I mean; i know what i need (ish), but i dont feel comfortable just ordering a breakout board and a bunch of drivers and motors and everything i need unless i know it's going to work together nicely (and me never having done this before seems a recipe for problems).

They make pre-built kits (i know - was thinking about getting this with a 5th driver option), but they're like 2x the cost of building your own.

Anyone have any recommendations on good, clear, videos or tutorials i can read up on to help me design my own controller kit? Or is that just a bad idea for a first timer; X-)?

 

Nice. And for about 90 bucks on the box, that works out great!

Unfortunately i won't be able to squash all my stuff in one of these :|. all Nema 34s, dual y-drive and we wanted the option for a 5 axis. Think it's going to be pretty pricey X-( ...Its so tempting at this point just to buy a pre-built package....but the cost is a good motivator to do it the hard way. X-)