Brother TC-S2Dn-0 Z Axis Deflection Spec in X Direction

[BugRobotics]

Doing some cleaning/checking on the mill this morning and noted about 0.0007" deflection on the Z axis housing (measuring directly below the spindle face on a tool holder) when I pushed/pulled a bit in the X direction. I was looking in the manuals and didn't see a spec for the Z axis side to side deflection and was wondering what others have seen in their Brothers. Y direction is tighter due to pushing/pulling against the linear rails and mass of the Z axis assembly. No real issues on finish or holding tolerances just curious. Any info is appreciated.

 

[DavidScott]

On my new R650 I don't get any movement with a tenths indicator in the Z axis with about 50 lbs of force, same for the Y axis. But I do get .0025" in X when doing the same, which is the only movement I get in any axis in any direction. Keep in mind it is a fixed table mill. I am very curious what others see.

 

[BugRobotics]

On my new R650 I don't get any movement with a tenths indicator in the Z axis with about 50 lbs of force, same for the Y axis. But I do get .0025" in X when doing the same, which is the only movement I get in any axis in any direction. Keep in mind it is a fixed table mill. I am very curious what others see.

I'll do it with 50lbs as well to compare and report back. I was using more like ~20lbs.

 

[DavidScott]

You might want to check your table movement as well while you are at it.

 

[Pete Deal]

I have one of the Maritool probe calibrator tools. I don't have a probe but just use it for stuff like this since it's all one piece and got a nice ground tip. On my TC-S2Dn-O with about a 20lb side load (guess) I get about .0002" deflection in X and Y. This machine does have about .001" runout in the spindle. I bought this machine used and it had a rough previous life as many of these machines do.

My S1000 spindle deflection is about the same as the above machine. This machine has only about .0001 or .0002" runout in the spindle.

 

[BugRobotics]

I have one of the Maritool probe calibrator tools. I don't have a probe but just use it for stuff like this since it's all one piece and got a nice ground tip. On my TC-S2Dn-O with about a 20lb side load (guess) I get about .0002" deflection in X and Y. This machine does have about .001" runout in the spindle. I bought this machine used and it had a rough previous life as many of these machines do.

My S1000 spindle deflection is about the same as the above machine. This machine has only about .0001 or .0002" runout in the spindle.

Yea, 0.0002" sounds more reasonable. I called Yamazen (central office) and they said they didn't have a spec (?) and that "yea, it should move a little". A bit underwhelming to say the least for my first call into the technical department.

 

[Pete Deal]

Well I wouldn't loose much sleep over it if it's doing it's job. Maybe when you have some time spend a little time indicating things to better see what's going on.

 

[couch]

Does any mtb report how much deflection the spindle has with 20-50lbs of force on the side of the spindle housing?

 

[BugRobotics]

Does any mtb report how much deflection the spindle has with 20-50lbs of force on the side of the spindle housing?

No I suspect not. But I guess I was expecting a bit more of a detailed response like..."We don't publish that spec but we use XYZ linear rails and the part number is ABC so you could run the calcs if you'd like"; which I'd happily do. It was just a total disinterest in the question and the answer that was surprising to me.

 

[hi-fly-cnc]

If you just push about that hard on the sheet metal outside, do you see similar deflection?

I wonder if you aren't just distorting the whole machine?

On my S700, if I put my hip against the door and push firmly in the Y axis direction I can see microns of movement relative between spindle and table... I guess these are lightweight machines... Levelling them appears to help?

 

[BugRobotics]

If you just push about that hard on the sheet metal outside, do you see similar deflection?

I wonder if you aren't just distorting the whole machine?

On my S700, if I put my hip against the door and push firmly in the Y axis direction I can see microns of movement relative between spindle and table... I guess these are lightweight machines... Levelling them appears to help?

I'll do some more testing this weekend and report back my findings. I'd doubt I'd see much deflection from manipulating the sheet metal but only way to know is to test.

 

[2outof3]

There is not a test result because it is not a test you would do on a machine tool. Pushing on the head or table tells you nothing except how a lever works. I have personally moved larger 40 inch VMC's by pushing on the table. More than tenths. It just showed I am large and can move a mass. If you want a machine that will not move under these situations, than a small fast machine is not for you. They are designed to move as a unit. Not one piece with force. If you build for that, than slip/stick becomes more of an issue.

 

[hi-fly-cnc]

Hi, just to be clear, I didn't mean that this was a sensible test. I was just pointing out that when we are talking about measuring microns and putting 50lbs of force on stuff, then it could be moving for reasons other than backlash

I meant only that if you push the whole machine then it will deform (in the microns range). However, pushing on the spindle is kinda like pushing on the whole machine as well. If the order of change is similar to pushing on the casting, then probably nothing wrong with any bearings. If the change is much larger than just pushing on the casting, then of course investigate further

 

[BugRobotics]

There is not a test result because it is not a test you would do on a machine tool. Pushing on the head or table tells you nothing except how a lever works. I have personally moved larger 40 inch VMC's by pushing on the table. More than tenths. It just showed I am large and can move a mass. If you want a machine that will not move under these situations, than a small fast machine is not for you. They are designed to move as a unit. Not one piece with force. If you build for that, than slip/stick becomes more of an issue.

I agree that this test wouldn't be something normally done if say the linear rails are new and installed properly. A machine with the linear rails loosened, screws that had somehow backed off on the linear rail mounting surface or say damaged linear bearings could show more than acceptable movement when manipulated. That movement would most likely come in the form of back and forth play not deflection (what I was seeing). Of course everything is rubber and will move no matter the magnitude of force applied. I check linear rails when I'm building a machine to verify that the rails are tight and I didn't forget to tighten the rails or the screws mounted to the top of the bearings.

Again no real issues with the machine or holding tolerances but I was curious as to what others are seeing.