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Re: Precision limit switches and lathe homing
Posted: Tue Dec 17, 2019 3:16 pm
by ScotY
Cool, thanks for the info! I guess I’ll try them and see. I don’t mind the cost as I only need one. Would be worth it to me to have to avoid the skim cut and measure ordeal.
Stupid question because I don’t use the lathe much and I’m not home at the moment...if I home X, then take a skim cut and measure, does the software remember the position when restarting the machine? I assume it does but never gave this much thought until now. Also, how do you adjust the homing speed?
Re: Precision limit switches and lathe homing
Posted: Tue Dec 17, 2019 11:33 pm
by mick41zxr
They are the Metrol Switches from Japan.
Very high quality & accuracy, have used them for a while with no problems.
Only issue I see is that the signal wire supplied is not shielded so you have to take that into consideration.
Re: Precision limit switches and lathe homing
Posted: Thu Dec 19, 2019 12:04 pm
by cbb1962
slodat wrote: ↑Tue Dec 17, 2019 12:18 pm
I use
these inductive proximity switches on my CNC router. My homing routine for each axis works like this:
- move to switch at 50ipm
- move opposite direction until switch clears at 5ipm
- move to switch at .1ipm
I have found this give very accurate homing, well within the accuracy/repeatability of my machine.
Would you share your .hom file?
Re: Precision limit switches and lathe homing
Posted: Sun Dec 22, 2019 1:46 pm
by slodat
Code: Select all
; 2019-12-22 Homing file
; cncm.hom
;
N100 ;Check for open home switch
IF ![#50001] THEN M225 #100 "X Axis Home Switch Tripped!!!\nPlease Clear Before Homing\nPress Cycle Cancel To End Homing"
IF ![#50002] THEN M225 #100 "Y Axis Home Switch Tripped!!!\nPlease Clear Before Homing\nPress Cycle Cancel To End Homing"
IF ![#50003] THEN M225 #100 "Z Axis Home Switch Tripped!!!\nPlease Clear Before Homing\nPress Cycle Cancel To End Homing"
M106 /Z P3 F15 ;Move Z at 15 ipm until input 3 (Z axis switch) opens
M105 /Z P-3 F5 ;Back Z off Switch
M106 /Z P3 F.1 ;Move Z at 0.1 ipm until input 3 opens
M26 /Z ;Set Z home here
M105 /Z P-3 F5 ;Back Z off Switch
M105 /Y P2 F50 ;Move Y at 50 ipm until input 2(Y axis switch) opens
M106 /Y P-2 F5 ;Back off Y Switch
M105 /Y P2 F.1 ;Move Y at 0.1 ipm until input 2(Y axis switch) opens
M26 /Y ;Set Y home here
M106 /Y P-2 F5 ;Back off Y Switch
M105 /X P1 F50 ;Move X at 50 ipm until input 1(X axis switch) opens
M106 /X P-1 F5 ;Back X axis switch
M105 /X P1 F.1 ;Move X at 0.1 ipm until input 1(X axis switch) opens
M26 /X ;Set X home here
M106 /X P-1 F5 ;Back X off X switch
g53 x0.1 y 0.1
N1000 ;END
Re: Precision limit switches and lathe homing
Posted: Mon Dec 23, 2019 10:50 am
by Muzzer
I've used Omron TL-Q proximity switches on my Bridgeport Z axis to good effect. These are eddy current devices, rather than Hall effect or variable reluctance, which means they work with most metals - and their sensing distance is quite a bit shorter with non-ferrous targets than ferrous ones (steel etc). The upshot is that they are likely to be several times more accurate when used with an aluminium target and they seem to be very repeatable. See the bottom of page 6 of the datasheet.
http://www.ia.omron.com/data_pdf/cat/tl ... csm468.pdf
They are widely available on ebay etc, in both NO and NC versions.