What's new
What's new

Tormach microArc 4th axis any good?

A CNC 4th has a hydraulic or air brake as part of the main spindle. That way cutting forces don't beat the gears to death and it will hold position.

That manual indexer with a stepper mounted scabbed onto it still has the manual spindle lock lever. That is how you would need to use it.

A servo doesn't need a brake unless gravity moves the axis when the power is off.

You are absolutely correct with the servo + brake. The servo would just be fighting the brake if both were engaged, makes sense.
If I plan on keeping the included stepper though, I would probably want a break so it doesnt lose steps when trying to hold position since open loop
I dont think open loop steppers belong in a cnc mill, but I will have to see how much use I get out of it before justifying a $800+ servo (I am just a home gamer after all)

I wonder if I can use a rotary air actuator/ cylinder to lock and unlock that brake instead of using the manual lever. I can guarantee I will forget to lock/ unlock that thing haha

"That manual indexer with a stepper mounted scabbed onto it"
Honestly I am becoming less and less impressed with Tormach by the minute. I watch guys like SMW at NYC CNC make great parts with tormachs, but the mechanical engineer in me cringes at some of the choices tormach makes to cost down these mills.

I know thats what yall have been saying all along, but I physically cant fit a Haas through my garage door haha
 
Please ..

Look at the specs and weights and torsional rigidity of a HAAS rotary table.

Approx 100x-1000x more rigidity.
Anything with a 85 mm PCD for mounting holes, of 6 mm, is a joke.

140 mm pcd x 4 x 8 mm shcs would be a good minimum start.
About 20x better (pwr 3 d iirc).


Their HRT160 gives me wet dreams, but $12K is outside of my price range right now haha
 
The brake goes on plate end of a rotary. Locking the drive side does not stop the gear wear or slop from moving parts. All moving parts have play. If it is a worm drive they self brake so putting a brake on the motor does nothing. Worried about holding power and dismissing steppers seems - lack of knowing - worm drives or motors. You are using almost a full 1/2 horsepower at those mmr. I am not sure how much of a rotary you need.
 
Their HRT160 gives me wet dreams, but $12K is outside of my price range right now haha

Haas rotaries really are bottom barrel. Pull that chinsy sheetmetal cover off the side and you'll see what I mean. A good used 8" or so 4th from a top name builder usually sells around $1500 to $2500 with controller. if you need a full 4th to integrate with something then that's a different story, but that's not what you said you needed in the start.

Let Haas people fight over Haas 4ths and buy one 10 times better for 1/10th the price.

What positioning do you actually need? If you just need even increments like 90-180-270 or even every 15 degrees or so you should look at an old Erickson air indexer. They are CNC controllable, way faster than you need and built like a tank, but still light and compact.
 
Haas rotaries really are bottom barrel. Pull that chinsy sheetmetal cover off the side and you'll see what I mean. A good used 8" or so 4th from a top name builder usually sells around $1500 to $2500 with controller. if you need a full 4th to integrate with something then that's a different story, but that's not what you said you needed in the start.

Let Haas people fight over Haas 4ths and buy one 10 times better for 1/10th the price.

What positioning do you actually need? If you just need even increments like 90-180-270 or even every 15 degrees or so you should look at an old Erickson air indexer. They are CNC controllable, way faster than you need and built like a tank, but still light and compact.

Honestly most of my stuff will be 90 degree indexes.

Right now I am doing a lot of very complex, but small UHMW parts that have holes and slots on all 6 sides. There is also usually a lot of material removal which means taking some off, flipping it over, taking more off, flipping it back, etc to prevent warping.

Basically these parts are taking me upwards of 10 setups to machine all 6 sides without warping.

It would be pretty nice to do the bulk of that work holding the part by a 50 thou dovetail on a 4th axis, then just put it in a standard vise to get the last side(s)

Other parts they have me milling slopes in delrin, like 72.5 degrees and weird angles that I have just been doing with a ball nose/ bull nose and a 5 thou stepover. Would save some cycle time to just do it with 4th axis

These parts range from 2x2x.25" to 6x4x1" out of delrin or UHMW and they all have surface finish callouts, no scratches or dings etc which is hard to do with so many setups and keeping everything clean.
They pay good, but it will take, no joke, all day to make one part, and if I accidently ding it, I have to start all over.

My want tho is to be able to murder 6061 with it as well, so I can do my aluminum parts more efficiently and take on more complex jobs that I have had to turn away.
 
You could get a regular manual rotary table and mount it up like a 4th. Just do your indexes manually (easy and fast without the extra hurdle of programming and controls to fuss with). Try that out to get your work flow and work holding dialed. You may realize you need something different than you are looking at now, or even that it’s not as efficient as you thought, without wasting a lot of time/money on a rabbit hole.
You will never regret having a manual rotary table, and a tilting rotary is really handy without all the fuss of a 5axis.
 
You are absolutely correct with the servo + brake. The servo would just be fighting the brake if both were engaged, makes sense.
If I plan on keeping the included stepper though, I would probably want a break so it doesnt lose steps when trying to hold position since open loop
I dont think open loop steppers belong in a cnc mill, but I will have to see how much use I get out of it before justifying a $800+ servo (I am just a home gamer after all)

I wonder if I can use a rotary air actuator/ cylinder to lock and unlock that brake instead of using the manual lever. I can guarantee I will forget to lock/ unlock that thing haha

"That manual indexer with a stepper mounted scabbed onto it"
Honestly I am becoming less and less impressed with Tormach by the minute. I watch guys like SMW at NYC CNC make great parts with tormachs, but the mechanical engineer in me cringes at some of the choices tormach makes to cost down these mills.

I know thats what yall have been saying all along, but I physically cant fit a Haas through my garage door haha

Why can’t you fit a haas (or other brand) through the door? I have a standard 7foot door and shoved a tm-1 and tm-2 into mine. Very easy. Lower the head. Loosen the energy chain and float it horizontal. Remove the break resistor box (1wire clip and 4 bolts.) bingo your 83.75” tall and good to go. you can lower it an additional 6”? If you remove the outrigger style feet on the lower casting. But be carful as it’s tippy
Heck, a year ago I skidded them out and tossed a vf2 with a side mount tool changer into the same 84” door. Lowered the head and removed the side mount tool changer. Slid right under. A carousel tool changer would go right under without removing a bolt if I remember correct (maybe the break resistor box?)
It’s very doable. Buy a pizza for your friends, get some machine rollers and your good. I prefer a picker truck for lifting, but forklifts work too used pretty small forklifts for the tm machines but it felt sketchy. Picker was way safer
Was a pain getting the smtc back on tho with limited overhead height and diy style lifting capacity. Bit do able
 








 
Back
Top