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lathe thermal growth mitagation solutions?

Stirling

Hot Rolled
Joined
Dec 11, 2013
Location
Alberta canada
playing with a new to me lathe. ran a batch of parts and slooowly comped thermal growth over several hours. approx 0.0022" very slow and consistant growth. shop probobly went up 2-4 deg through the run as well.
then took a 10-15 min break and it cut the next part 0.0016 smaller than the last. She shrunk fast!!!!! this might be a real problem kicking the door open once in a while. +20 inside and its -25C outsidein winter ... anywhooooo.

now its got me wondering what i can do to mitigate the majority of the growth in the first place?
my simple ideas:
add a pond pump and radiaror to take some heat out of the coolant. place the radiator atop the mistaway to blow the heat out?
add a few fans to the enclosure to pump shop air through to reduce the heat buildup

any other simple ideas?

i dont have much extra power i can throuw at it, pretty power limited unfortunatly
 
-25C winters, fellow Canadian by any chance?

I don't have any recommendations to cool down the machine, but if the thermal growth is as you say consistent and measurable, then it can be accounted for. You could conceivably use a macro to compensate for it as you run your production, though you would need to reset it when you take pauses.
 
Also, while it wouldn't hurt to take heat out of your coolant, I'm doubtful that it would have much effect on reducing temperatures at the ball screws which is where the temperature rise would have the most effect, but I'd be glad to be wrong.
 
playing with a new to me lathe. ran a batch of parts and slooowly comped thermal growth over several hours. approx 0.0022" very slow and consistant growth. shop probobly went up 2-4 deg through the run as well.
then took a 10-15 min break and it cut the next part 0.0016 smaller than the last. She shrunk fast!!!!! this might be a real problem kicking the door open once in a while. +20 inside and its -25C outsidein winter ... anywhooooo.

now its got me wondering what i can do to mitigate the majority of the growth in the first place?
my simple ideas:
add a pond pump and radiaror to take some heat out of the coolant. place the radiator atop the mistaway to blow the heat out?
add a few fans to the enclosure to pump shop air through to reduce the heat buildup

any other simple ideas?

i dont have much extra power i can throuw at it, pretty power limited unfortunatly
bigger sump/oil cooler for the hydraulic system, maybe a cooler for the coolant, but both are limited by the ballscrews.

Running a warm up cycle in the mornings, and when on extended breaks seems to help, Ran a Deawoo/doosan that was susceptible to temp swings, do yer best to keep cold drafts away and keep it choochin on a warm up cycle seems to help, wasn't perfect, but it was fairly predictable Perhaps some el cheapo cubicle walls, or welding curtains? for exter winter time protection? (lame Idea but its better then nuthin I guess?)

weirdly my new to me manual lathe has an oil cooler for the headstock, not the foggiest idea as to why... but there it is
 
Agree with Northman Ind., your first line of mitigation is to keep the machine at its warm thermal equilibrium by running warm up cycles whenever it's not producing.
 
That seems like a lot of movement in a short amount of time. I wouldn't want a machine that did that in my shop. Are you sure there isn't something else going on? Does the machine have thermal comp?
 
That seems like a lot of movement in a short amount of time. I wouldn't want a machine that did that in my shop. Are you sure there isn't something else going on? Does the machine have thermal comp?
that was my thought. it was a nice slow predicatable rise over several hours. very sustainable. then the sub chuck stoppe working. was not opening. apperently the pickup got loose and shifted just enough, but i found it quick and got back too it. i was shocked at how quick it "shrunk"
my other lathe would never react so drasticaly.

hence exploring small solutions that may help a little.

as for thermal comp, as far as i know its turned off, unless it has more than one method in the machine? its a nak amura as200l. from what i see it uses theal comp by measuring the coolant sump temp. the sensor is unplugged and option deativated in the controler. ill have to try it out sometime

as for shrouding from draft, no go, im in a 22x22 garage!
 
bigger sump/oil cooler for the hydraulic system, maybe a cooler for the coolant, but both are limited by the ballscrews.

Running a warm up cycle in the mornings, and when on extended breaks seems to help, Ran a Deawoo/doosan that was susceptible to temp swings, do yer best to keep cold drafts away and keep it choochin on a warm up cycle seems to help, wasn't perfect, but it was fairly predictable Perhaps some el cheapo cubicle walls, or welding curtains? for exter winter time protection? (lame Idea but its better then nuthin I guess?)

weirdly my new to me manual lathe has an oil cooler for the headstock, not the foggiest idea as to why... but there it is
thats pretty much what i want to avoid, "suceptibility to temp swings" or at least limit the effects. a 0.0005" size change would have been ok.. but 0.0016. thats alot quickly
i work in my little 22x22 garage so it heats up while working, if i crack the door their can be inconsistant wind and anywhere from +30c - -40C depending on the season (ya northern canada ;p )

not looking for a magic solution, but any tips people have found over the year can add up and make things more predictable. always better to have hardware/process solutions rather than relying solely on software and guessing
need more hours on it. play with the thermal comp and stuff.
 
that was my thought. it was a nice slow predicatable rise over several hours. very sustainable. then the sub chuck stoppe working. was not opening. apperently the pickup got loose and shifted just enough, but i found it quick and got back too it. i was shocked at how quick it "shrunk"
my other lathe would never react so drasticaly.

hence exploring small solutions that may help a little.

as for thermal comp, as far as i know its turned off, unless it has more than one method in the machine? its a nak amura as200l. from what i see it uses theal comp by measuring the coolant sump temp. the sensor is unplugged and option deativated in the controler. ill have to try it out sometime

as for shrouding from draft, no go, im in a 22x22 garage!
well... just lock yerself in until spring duh...

What yer describing as far as movement, is on par with what I've dealt with on other machines that didn't have thermal comp. there's more to the system then a sensor and a setting though, usually a boxy looking radiator, and a bunch of piping throughout the machine.

Fadal mills, the really cheap ones with the greased ways... would really jump with a good workout, didn't stop the shop owner on insisting we hold .005" on a 4hr cycle time...
 
that was my thought. it was a nice slow predicatable rise over several hours. very sustainable. then the sub chuck stoppe working. was not opening. apperently the pickup got loose and shifted just enough, but i found it quick and got back too it. i was shocked at how quick it "shrunk"
my other lathe would never react so drasticaly.

hence exploring small solutions that may help a little.

as for thermal comp, as far as i know its turned off, unless it has more than one method in the machine? its a nak amura as200l. from what i see it uses theal comp by measuring the coolant sump temp. the sensor is unplugged and option deativated in the controler. ill have to try it out sometime

as for shrouding from draft, no go, im in a 22x22 garage!
Even your initial .0022" growth over a few hours seems wrong to me.
I can see .0005" to .001" in the first hour, but it should be settled after that.
Maybe I'm just lucky with my machines.
I would consider calling Elliot or whoever your Nak dealer is up there and explain to them what you're seeing.
Does anyone else see this much thermal growth in their lathes?
 
Does anyone else see this much thermal growth in their lathes?
Nothing like the OP, on the lathe I use the most (Emco Turn 325) if I stop for lunch and leave it sitting it'll drop 0.005mm/0.0002" to 0.01mm/0.0004" on diameters and then be back to how it was after two or three parts.

I'm also in the mindset of not to let it cool much once it's warmed up rather than trying to stop it warming up, sometimes that means having lunch when a fresh bar goes into the bar feeder or just trying to eat and work, I wouldn't even entertain anything like opening my roller door if the outside temp is lower unless I absolutely have to. I would guess being in a small confined shop air quality might be a conern in which case I'd invest in mist collectors/air filtration or just go outside if you need some fresh air while the lathe is running, not trying to bring the fresh air inside.
 
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I used to have a Doosan S310SMLY that was the same, fairly stable when it was running constantly but all over the place while it was warming up or if it stood for half an hour over lunch etc.

On that machine it was all spindle growth, not much to do except for keep it running...

I don't have a Y axis lathe anymore, which I miss sometimes, but otherwise I don't miss that Doosan at all.
 
The X ballscrew is the biggest player in thermal growth issues, and one thing that you CAN doo to mitigate this is to keep your X motions to a min.

In stead of running home in X to clear for a tool change, rapid to a clear point in Z to run your tool changes.


------------------------

I am Ox and I approve this here post!
 
Nothing like the OP, on the lathe I use the most (Emco Turn 325) if I stop for lunch and leave it sitting it'll drop 0.005mm/0.0002" to 0.01mm/0.0004" on diameters and then be back to how it was after two or three parts.

I'm also in the mindset of not to let it cool much once it's warmed up rather than trying to stop it warming up, sometimes that means having lunch when a fresh bar goes into the bar feeder or just trying to eat and work, I wouldn't even entertain anything like opening my roller door if the outside temp is lower unless I absolutely have to. I would guess being in a small confined shop air quality might be a conern in which case I'd invest in mist collectors/air filtration or just go outside if you need some fresh air while the lathe is running, not trying to bring the fresh air inside.

I’ve added a mistaway to the machine. Otherwise I’d need a mask all day!
I have found that adding a mistaway really cranks up the shop humidity though, but it’s not misty anymore at least.
I’ll need to add a fresh air exchanger to combat this.

I typically do not leave the machine when doing any precision work. Keep it warm and consistent.
I was just shocked at how quickly this lathe shrunk after I had to stop to correct the chuck mag pickup, I’m new to this lathe and dont want it to “become a problem”
Hence exploring ways to minimize growth in the first place.

My main season for opening the door is to move my chips outside.
It all dumps into 5gallon pails and I toss it in my truck.
I’ll have to let them collect inside for longer inside
 
The X ballscrew is the biggest player in thermal growth issues, and one thing that you CAN doo to mitigate this is to keep your X motions to a min.

In stead of running home in X to clear for a tool change, rapid to a clear point in Z to run your tool changes.


------------------------

I am Ox and I approve this here post!
Good point.
This lathe does do a lot more x moves than my last one the way it’s programmed now

I’m brand new to fanuc so I’ll need to learn how to change the tool change position.
You run fanuc Nak lathes.
How do you go about this?

I’d assume either changing a parameter or something in each program that alters it temporarily?

My last lathe was all conversational and you’d set it right at the Home Screen for each job.
 
I used to have a Doosan S310SMLY that was the same, fairly stable when it was running constantly but all over the place while it was warming up or if it stood for half an hour over lunch etc.

On that machine it was all spindle growth, not much to do except for keep it running...

I don't have a Y axis lathe anymore, which I miss sometimes, but otherwise I don't miss that Doosan at all.
Was the spindle growth causing diameter movement? I don't understand how that happens unless there is something wrong with the spindle. Maybe you mean that it caused length movement?
 
Good point.
This lathe does do a lot more x moves than my last one the way it’s programmed now

I’m brand new to fanuc so I’ll need to learn how to change the tool change position.
You run fanuc Nak lathes.
How do you go about this?

I’d assume either changing a parameter or something in each program that alters it temporarily?

My last lathe was all conversational and you’d set it right at the Home Screen for each job.

I doo have a cpl of Naks that we got recently, but I'm not real sure of an easy way to go about this on the Nak.

On my other Fanuc lathes, I just call a:

G0 T0 Z14.

or to whatever Z ref point that all tools clear the part, and then I can use that anywhere in the program.

But the Nak's don't want to allow a T0 entry, and I haven't found a way to edit that yet.

So, in that case, what you can doo is call a:

N1 T101
.
.
.
G0 T100 Z14.

N2 T202
.
.
.
.
G0 T200 Z14.


But you need to be sure that you don't put a tool in a different pocket the next time that you set it up, or if you doo, then you need to edit the G0 line.

I have no clue why Nak would not allow a T0?
Must be some safety reason, but I don't understand how that would be, and it causes me a bunch of grief.

I have seen in the M code registry (14 page long list for the 8x lathes!) that they have up to maybe 3 REF locations that you can call.
I have not looked into those, so IDK how to edit those points at this time, but that may be a good option to look into.

Hardinge machines are a LOT easier to run!


---------------------

I am Ox and I approve this here post!
 
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Was the spindle growth causing diameter movement? I don't understand how that happens unless there is something wrong with the spindle. Maybe you mean that it caused length movement?

Yes, it caused diameter movement as the spindle housing casting warmed up.

The spindle itself expanding will cause only axial movement. The housing warming up will cause the physical position of the spindle to deviate.

Think about how a VMC drifts in Y as it heats up.
 








 
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