Low cost CNC indexing options

Hi,

I am currently working on bringing spline milling in house at the company I work for, we have a small Haas TM-1P that sits idle 80% of the time so we want to put it to good use and use it to spline all the shafts we manufacture.

However we are trying to do this for as little cost as possible, which is why we are trying to avoid using a Haas rotary head as they cost £10000 + £2000 for the 4th axis option. Another reason we are not wanting to spend this amount of money is that it is over-kill for what we need, we do not need 4th axis capability, we only need to be able to increment X number of degrees, cut a spline, index, cut a spline, index etc... it is not worth spending that much money on 4th axis capability that wont be used.

So my question is, what other options do we have for simple CNC rotary indexing? We were thinking that there may be a solution that allows us to set an increment size and then connect the indexer to the bank of M code relays and simply index by commanding an M code? Im curious to see if anyone else has done something similar? Surely there must be a solution to this problem as only simple incremental indexing is needed.

Any suggestions would be appreciated!

You could cobble some stuff together for 2-5k but if you or the boss won’t invest 12k to turn a idle machine into a loss leader what’s the point? If doing it the right way won’t pay, doing it the wrong way won’t either. You will just waste a lot of time figuring it out.

You don't need to run the Haas rotary as full 4th. You can just buy the external box that indexes incrementally and is triggered by M code.

Cheaper would be a Superspacer w/tailstock. Manually index after each spline. You'd need a plate with the proper no. of indexes.

Even cheaper, and something I have done, is make a sleeve that fits the OD of your shaft. Stand it on end and mill equally spaced flats around the outside that matches the no. of teeth on your spline.
Rest on a flat, mill a tooth. Rotate to the next flat, mill a tooth, etc.

Aejgx6, Not really the kind of answer I was looking for.

It would the return on investment would be <12 months even when spending 12k, but if there are alternatives that could save 7k then why would we turn our noses up at that solution? Whats to say that is the "wrong solution"?

Yes but you still have to buy the 10k haas rotary with that idea.

Good ideas but because of the volume of shafts we produce we really need CNC indexing.

Some time ago there was a thread about an indexer that could be advanced by pushing a button mounted on the table with the spindle. I think it was the guy in California(LA area?) that used to inundate us with rookie type questions ranging from very good to WTF is he thinking.

options:
1) new, full function, haas 4th = $10K
2) used, any brand, stand alone 4th w/ controller $2-6K
3) Super Spacer = $800
4) used, pneumatic indexer = $1-2K
5) used, mechanical, push button indexer = $1000

The prices are what I could find easily on ebay or machinetools.com

Doug.

alphonso said:

Some time ago there was a thread about an indexer that could be advanced by pushing a button mounted on the table with the spindle. I think it was the guy in California(LA area?) that used to inundate us with rookie type questions ranging from very good to WTF is he thinking.

Click to expand...

Solar????

The push button indexer would be a good (and cheap) option for the OP.

alphonso said:

Some time ago there was a thread about an indexer that could be advanced by pushing a button mounted on the table with the spindle. I think it was the guy in California(LA area?) that used to inundate us with rookie type questions ranging from very good to WTF is he thinking.

Click to expand...

Solar71.. He hasn't been around in a while. He was fun. PI hated his guts...

Thats the one I was thinking of also.. It was a plunger on the top of the 4th, and it indexed XXX degrees
for however far you pushed down on it.. I have no idea what it was called. But it required zero electronics,
just needed some creative programming..

I played around with manual indexers and fixtures with flats machined in for similar applications... then I ponied up and bought a 5C indexer from Haas. It was the best money I spent.

You could probably cobble something together that could be automated by the spindle or M code, but like someone said, it is still going to cost a couple of grand in parts and many hours to get to function. If the ROI is not sufficient to justify the rotary, I would probably keep farming them out.

Kristian30041995 said:

Yes but you still have to buy the 10k haas rotary with that idea.

Good ideas but because of the volume of shafts we produce we really need CNC indexing.

Click to expand...

I picked up a new HRT210 from Leopard_machine_sales for around 6K a couple of years ago.
Of course, that was during the recession.

Short answer is yes, you can buy an indexer to run off your machines M-code.

Old Haas rotaries and indexers with a box can run this way too.
Old brings up used...

Other cheap alternatives would be to made index fixtures...could even make automatic with M-switches to clamp unclamp parts and use the spindle to index.


I do want to point out...your kinda talking out both sides of your mouth when you say you want cheap as the parts do not call for full 4th then you say you have a bunch of them to do and need it to be a CNC automatic operation.


I am just going to toss something out at you to think about...Yes you can buy indexers with controls to run off M-Codes. They will work and be automatic. You can program the controls to index however many degrees you need, then trigger with your Haas Controls M-Code.

-But in doing that you will have TWO areas that you can introduce error and make a mistake.
-You will need to Program two Controls and verify both work correctly.
-Each part with a different degree needs to call up a new program for both Controls.

-Works and works well, but cumbersome with double the potential error.
-While not difficult to program indexers, they are a bit more involved then doing it in the main program and your readout of position is on the units control.


What is nice about the Haas Rotary, once the program is proven you just setup part, call up program in the Control and push the Go-Go Green Button. You can verify just by looking the index degree on your controls screen if all is correct, no chance of mistakes. Quick clean and easy.

To program a move...it is a simple "G0 A15." in the program...not a M* (should be 15 deg)

Now bring that back to you...yes there is expense to a rotary/indexer. But if you have the work it pays itself off, plus you increase the machines versatility.
Part of the payoff is decreased error, speed of programming and setup.


Obviously I do not know your position, but almost sounds penny wise and dollar foolish as you already say you have the work to justify the investment.

Good luck either way.

search Erickson speed indexer on this site. there are some threads like this that i have replied my results with this indexer which is basically a push button to index pneumatic indexer., though minimum degrees of rotation for splines may be a problem and may require more than a custom index plate.

Kristian30041995 said:

However we are trying to do this for as little cost as possible, which is why we are trying to avoid using a Haas rotary head as they cost £10000 + £2000 for the 4th axis option. Another reason we are not wanting to spend this amount of money is that it is over-kill for what we need, we do not need 4th axis capability, we only need to be able to increment X number of degrees, cut a spline, index, cut a spline, index etc... it is not worth spending that much money on 4th axis capability that wont be used.

Click to expand...

The thing about the HAAS 4th is that it is fully engineered and proven. If it does what you need, it is unlikely that you will be able to buy other new systems for less. If you can find something used, then you might be able to get it cheaper.

You basically have two choices for indexing:
1) Servo indexing. This is what the HAAS will use.
2) Mechanical indexing. Pins, Hirth couplings, pawls, etc

Even if it is M-code controlled, you aren't likely to get option 1 for significantly less money. And then you still have the cost of integrating it to your control, and debugging it. And the indexer has the native full 4th functionality that the HAAS has, so you're paying for it anyway, but the capability is neutered by the control interface.

For the second option, you're into precision machined parts, if you need accurate indexes. Then you're trading off the cost of precision mechanical index components vs. the cost of the servo. Then you add the cost of the actuators and controls on top if you want the CNC control to be able to index. Then you need to be able to handle the connections to feed errors back to the control to let it know if it finished indexing. And to finish it off, you have less indexing options than the full 4th.

Booze Daily said:

Even cheaper, and something I have done, is make a sleeve that fits the OD of your shaft. Stand it on end and mill equally spaced flats around the outside that matches the no. of teeth on your spline.
Rest on a flat, mill a tooth. Rotate to the next flat, mill a tooth, etc.

Click to expand...

have done similar things like making a collar with carefully spaced dowel holes and rotating them onto a stop, we did this for cylinders with multiple slots with odd spacing. also built a set of punch and die rings by putting dowel holes (around 88 if I remember right) on the face of the ring, which was left with excess stock, final operation, face off excess stock.


gotta say, this is effective cheap indexing for one, two offs, if youre gonna make splines even a few days a week, get the best auto indexing you can afford.

First, is your idle machine already wired for a 4th axis and does the control have that option turned on? If not, upgrading the machine will likely cost as much as the indexer.

If it's 4th axis ready just buy a Haas HA5C with as many heads as will fit in the machine (assuming your shaft diameter will pass thru a 5C collet). On a 40 x 20 table it is most effective to mount the unit using the near slot with the collets facing away from the operator. Better access to the piping and valves, as well as being able to whack a stuck workpiece with a soft hammer.

If you settle for a manually operated indexer you might as well be tending a Bridgeport...

Kristian30041995 said:

Hi,

I am currently working on bringing spline milling in house at the company I work for, we have a small Haas TM-1P that sits idle 80% of the time so we want to put it to good use and use it to spline all the shafts we manufacture.

However we are trying to do this for as little cost as possible, which is why we are trying to avoid using a Haas rotary head as they cost £10000 + £2000 for the 4th axis option. Another reason we are not wanting to spend this amount of money is that it is over-kill for what we need, we do not need 4th axis capability, we only need to be able to increment X number of degrees, cut a spline, index, cut a spline, index etc... it is not worth spending that much money on 4th axis capability that wont be used.

So my question is, what other options do we have for simple CNC rotary indexing? We were thinking that there may be a solution that allows us to set an increment size and then connect the indexer to the bank of M code relays and simply index by commanding an M code? Im curious to see if anyone else has done something similar? Surely there must be a solution to this problem as only simple incremental indexing is needed.

Any suggestions would be appreciated!

Click to expand...

What spline are you cutting? Is it something you can buy a wheel type cutter for? If you are farming them out currently, they are, perhaps, being hobbed?

HuFlungDung beat me to it!

Find yourself an old Barber Colman hobbing machine (6-10, 16-32, whatever you need to cover the length). Yes... hobs (the actual cutter) are not cheap, but you can cut many different tooth counts of the same DP/PA using the same hob. Best part is... your CNC mill is still free to do other things, and the hob will just work away tirelessly cutting the splines.


PM

HuFlungDung said:

What spline are you cutting? Is it something you can buy a wheel type cutter for? If you are farming them out currently, they are, perhaps, being hobbed?

Click to expand...

The OP might not know what hobbing is or he wouldn't be asking about milling. Unless they are SAE parallel splines; you can still buy cutters for those. A photo would reveal whether they are being hobbed.

adamm said:

You basically have two choices for indexing:
1) Servo indexing. This is what the HAAS will use.
2) Mechanical indexing. Pins, Hirth couplings, pawls, etc
.

Click to expand...

Do you have a link to a diagram of any of these mechanical indexing mechanisms?

HuFlungDung said:

What spline are you cutting? Is it something you can buy a wheel type cutter for? If you are farming them out currently, they are, perhaps, being hobbed?

Click to expand...

We are cutting ANSI B92.1 class 6 splines. What would be the benefits of using a wheel type cutter?