CNC lathe for prototyping

kenton · May 18, 2018

My place of employment is looking to replace our 16 X 40 Bridgeport EZ path lathe with something newer and more well supported.

We are a prototype shop that does almost no production, our need for a CNC lathe is driven by part complexity. Our shop has ProtoTrak CNC mills, the EZ path lathe, a Mitsubishi WEDM and manual mills and lathes. We predominantly use the conversational programing when available but also use Surfcam software if part complexity requires it.

I have been focusing on conventional bed lathes, with a tailstock and steady rests, but might be open to other options. I would like to stay in the same size class but might be willing to down size a little. In the past few years we have been doing a lot of complex, deep internal bores so having a spindle that will run at 50 RPM would be an asset for us. We need to be able to run G code and have a post for surfcam, but having conversational programing would be a definite plus.

And the kicker, the shop is in a basement so the machine needs to be able to be disassembled to fit through a 48" door and into a freight elevator that measures 60" X 96"

I have been looking at Southwest's 1630sx and 1845sx and Haas's TL-1 and TL-2.

Any suggestions of other machines that might fit the criteria or any personal experience with any of the suggested machines would be appreciated.

Joe Miranda · May 18, 2018

I can't speak to the Haas lathes but I have two ProtoTraks and I really like them. One is about a '07 and the other is a '17. I think they are awesome for one offs.

I also have a '99 Milltronics that I think is a really good machine - very few issues and still repeatable.

HuFlungDung · May 18, 2018

kenton said:
I have been focusing on conventional bed lathes, with a tailstock and steady rests, but might be open to other options. I would like to stay in the same size class but might be willing to down size a little. In the past few years we have been doing a lot of complex, deep internal bores so having a spindle that will run at 50 RPM would be an asset for us. We need to be able to run G code and have a post for surfcam, but having conversational programing would be a definite plus.

50rpm? With some oomph or just enough gumption to turn itself over? You'd need a gearbox machine to get that low and be able to do much with it, doesn't much matter what HP it claims to have, it needs a lot of torque to be even remotely useful.

kenton · May 18, 2018

HuFlungDung said:
50rpm? With some oomph or just enough gumption to turn itself over? You'd need a gearbox machine to get that low and be able to do much with it, doesn't much matter what HP it claims to have, it needs a lot of torque to be even remotely useful.

I'd like to have some oomph. But realistically the EZ path can only do maybe .020 depth of cut and .004 per rev in AL at 50 RPM. It gets the job done but it's sure slow going.

I know what I'm asking may not be realistic but I can dream can't I?

HuFlungDung · May 18, 2018

So why are you cutting so slow in aluminum? Is it the solution to a vibration problem? Maybe you need to beef up your tooling.

Karl_T · May 18, 2018

You will like soutwest's conversation interface. Have not run or even seen that particular lathe. They do have good customer service and support.

kenton · May 23, 2018

HuFlungDung said:
So why are you cutting so slow in aluminum? Is it the solution to a vibration problem? Maybe you need to beef up your tooling.

Yeah, Vibration. I roughed out as much as I could with bigger tools but the bores have a small minimum dia and we couldn't have blend lines on the finish.

Also, sorry for the slow response, I've been down with the flu.

BSCustoms · May 23, 2018

If you are capable of learning g code to a comfortable level I would suggest the HAAS over proto trak. We have A LOT of prototrak machines. (I would bet a beer that our building has more than the west coast). They are fine machines for their intended use. But a bit limited and not meant to be run long and hard. Dollars to spindle the HAAS is cheaper. Southwest does have a fantastic conversational interface, once you learn how to trick it to do certain things. HAAS has better support and resale as well.

Either machine will suit you well for what you describe however.

HuFlungDung · May 23, 2018

kenton said:
Yeah, Vibration. I roughed out as much as I could with bigger tools but the bores have a small minimum dia and we couldn't have blend lines on the finish.

Also, sorry for the slow response, I've been down with the flu.

What size bores give the trouble? What shape tooling are you using? Insert shape and position are primary factors to play with to try to get a handle on vibration issues. If you can kill the low rpm requirement, it would be a good thing and I don't doubt you'd getter a better finish as well.

kenton · May 23, 2018

HuFlungDung said:
What size bores give the trouble? What shape tooling are you using? Insert shape and position are primary factors to play with to try to get a handle on vibration issues. If you can kill the low rpm requirement, it would be a good thing and I don't doubt you'd getter a better finish as well.

CCMT insert, .015 radius, .75 bar, .9something min diameter, 8.something deep in aluminum (It's been a while)

hand ground hss, "dead sharp", 1in shopmade bar, 1.181 min dia, 11.81 deep, in acrylic

I have been thinking about making a bar with a tapered back side made to fit the profile of whatever bore comes up next to try and increase my rigidity.

kenton · May 23, 2018

BSCustoms said:
If you are capable of learning g code to a comfortable level I would suggest the HAAS over proto trak. We have A LOT of prototrak machines. (I would bet a beer that our building has more than the west coast). They are fine machines for their intended use. But a bit limited and not meant to be run long and hard. Dollars to spindle the HAAS is cheaper. Southwest does have a fantastic conversational interface, once you learn how to trick it to do certain things. HAAS has better support and resale as well.

Either machine will suit you well for what you describe however.

That's good to hear, though we really don't run anything that hard. Our CNC lathe probably runs 15 hours a week when it's busy and it is rarely busy.

Have you ever run your prototraks on G code? Our prototrak mills can do it but it's kind of clumsy to use and you can't edit anything on the control.

HuFlungDung · May 23, 2018

kenton said:
CCMT insert, .015 radius, .75 bar, .9something min diameter, 8.something deep in aluminum (It's been a while)

hand ground hss, "dead sharp", 1in shopmade bar, 1.181 min dia, 11.81 deep, in acrylic

I have been thinking about making a bar with a tapered back side made to fit the profile of whatever bore comes up next to try and increase my rigidity.

That's a common thing those CCMT inserts. Everybody seems to make nice sets of these bars and everybody buys them, but they're not good performers on extended reach. You'd be better off with a more pointy insert like a T, D or even V if you have the room for it. C inserts will work a lot better if they're set at about 80 degree lead angle instead of 90, but then you can't get right to the bottom of a flat bore or shoulder, so not very versatile.

Also Iscar cutgrip might be worth looking at as the insert sticks out quite a ways if you need to profile internally, equip it with a full radius insert.

hanermo · May 23, 2018

I suggest you buy a proper industrial insert tool in solid carbide.
These are around 5x more rigid.

You seem to try to bore 12" == 300 mm deep with a == 20 mm boring bar or 1:15.
This is about 5x too much.
The acrylic material got you through it until ..

I can think of at least 3 different diy mcgiver-fixes that might fix it.
-Lead inside steel sleeve for boring bar. Kills chatter.
-A hydraulic soft collar in rubber, pressure fed via any coolant/liquid of choice.
-Rigid collar riding in the bore, non-marring, bronze/sintered sleeves, doing peck- boring.

Honing/Reaming the final diameter of the hole would be a great option.
Using an industrial plated diamond tool. Rigid tool in steel.
Auto engine blocks cylinder bores are done with these, and the tools last 200k+ cycles.
The op takes == 15 secs and gets 0.01 mm TIR and size of 0.01 mm, give or take.
A tool costs about 2 k.

If the hole is open, line bore it maybe ?

Like always.
How many, how fast, how good, how much in $ ?

E.
I might make similar for 3-500€ each in 1-1.5 micron +/- tolerances, in ID and tir over 200 mm length.
A true 1 micron accuracy over 300 mm would probably cost 50k each in qty 100.
And a major NEC or engineering charge.

If you can use a rigid solid steel diamond plated tool to finish it, sub 0.01 mm cylindricity and TIR and size are likely in less than 20 secs.

My comments try to be examples of industrial stuff and costs.
And I try to include some data for real comparison.

For example, any high end modern horizontal or vertical mill could finish the bores in a short time.
And would probably use solid carbide tool(s)(or sc shanks) to do so.

kenton said:
CCMT insert, .015 radius, .75 bar, .9something min diameter, 8.something deep in aluminum (It's been a while)

hand ground hss, "dead sharp", 1in shopmade bar, 1.181 min dia, 11.81 deep, in acrylic

I have been thinking about making a bar with a tapered back side made to fit the profile of whatever bore comes up next to try and increase my rigidity.

kenton · May 23, 2018

hanermo said:
I suggest you buy a proper industrial insert tool in solid carbide.
These are around 5x more rigid.

You seem to try to bore 12" == 300 mm deep with a == 20 mm boring bar or 1:15.
This is about 5x too much.
The acrylic material got you through it until ..

I can think of at least 3 different diy mcgiver-fixes that might fix it.
-Lead inside steel sleeve for boring bar. Kills chatter.
-A hydraulic soft collar in rubber, pressure fed via any coolant/liquid of choice.
-Rigid collar riding in the bore, non-marring, bronze/sintered sleeves, doing peck- boring.

Honing/Reaming the final diameter of the hole would be a great option.
Using an industrial plated diamond tool. Rigid tool in steel.
Auto engine blocks cylinder bores are done with these, and the tools last 200k+ cycles.
The op takes == 15 secs and gets 0.01 mm TIR and size of 0.01 mm, give or take.
A tool costs about 2 k.

If the hole is open, line bore it maybe ?

Like always.
How many, how fast, how good, how much in $ ?

E.
I might make similar for 3-500€ each in 1-1.5 micron +/- tolerances, in ID and tir over 200 mm length.
A true 1 micron accuracy over 300 mm would probably cost 50k each in qty 100.
And a major NEC or engineering charge.

If you can use a rigid solid steel diamond plated tool to finish it, sub 0.01 mm cylindricity and TIR and size are likely in less than 20 secs.

My comments try to be examples of industrial stuff and costs.
And I try to include some data for real comparison.

For example, any high end modern horizontal or vertical mill could finish the bores in a short time.
And would probably use solid carbide tool(s)(or sc shanks) to do so.

None of this is actually relevant to my question. But....
The bores are generally at least tapered, or more usually, concave or convex with a continuously changing radius. So line boring is out. We looked at a solid carbide boring bar but management decided it was too expensive. I thought about some kind of dampening weight but decided to just make the job work instead.

If in your experiences you have ever used a CNC lathes that met or were similar to the criteria in the first post that you would recommend, I would love to hear about it.

Chevy427z · May 23, 2018

I haven't seen much talk about the Haas lathes. I ran a TL-3 and absolutely loved it for prototyping. I've really been impressed with how user friendly Haas makes their controllers. The real beauty is being able to bounce back and forth between a mill and a lathe because the controllers are so similar. I chuckled when I read what you are trying to upgrade from. I have your same lathe in my garage. It's been giving me grief electronically and having a hard time finding someone local who can work on it. I am actually looking for a TL-1 or 2 to upgrade it to. Good luck on your quest!

Mark

hanermo · May 23, 2018

In my experience the very good apps. engineers we employed, 50+ cnc apps engineers on-staff, would not suggest lathe stuff but tooling stuff as I said.

So get a solid carbide boring bar.
As I said.

kenton said:
If in your experiences you have ever used a CNC lathes that met or were similar to the criteria in the first post that you would recommend, I would love to hear about it.

Mebfab · May 23, 2018

We just bought brand new southwest 1630. Great control. Fantastic for one offs or small handfull of parts. Fast and easy to learn. Be nice if the lathe where bigger and much heavier, but i was trained on old american iron......

kenton · May 23, 2018

hanermo said:
In my experience the very good apps. engineers we employed, 50+ cnc apps engineers on-staff, would not suggest lathe stuff but tooling stuff as I said.

So get a solid carbide boring bar.
As I said.

The question was "what should my shop replace our current, unsupported, out dated, unreliable lathe with".

Not "how should I run a particular type of job, that seems to come around once or twice a year". That was just a rabbit trail we went down.

kenton · May 23, 2018

If anyone has any suggestions or experience with any other brands of bed lathes I would love to hear it. I've been doing some more searching and I'm surprised how many manufactures offer lathes in that format. Or maybe they are all the same lathe with different software and sheet metal? Or maybe just different paint?

rcoope · May 23, 2018

We've been really happy with our 2007 TL-1 since it was bought new. This is in a hospital machine shop that does a lot of biomedical device prototyping. The conversational part of the control works well, much better than the Haas mills of the time. They are relatively affordable so I would take a serious look.

CNC lathe for prototyping

Stainless

Titanium

Diamond

Stainless

Diamond

Cast Iron

Stainless

Cast Iron

Diamond

Stainless

Stainless

Diamond

Titanium

Stainless

Stainless

Titanium

Diamond

Stainless

Stainless

Stainless

Similar threads