Microturn cutter head won't move
Moderators: Martin, Steve, Mr Magoo
Microturn cutter head won't move
Problem: Microturn – X & Z axis motors run and get warm to the touch but motion is not transferred to the carriage of the lathe and I can’t get the cutter head to move or engage into the work. With manual mode on the computer I can rotate the spindle.
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bradders
- CNC Guru
- Posts: 1251
- Joined: Mon 13 Feb , 2006 12:35 pm
- Location: Brighouse, England
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Resolution: The stepper motors do get hot when the machine is on. Take the back off the machine and check the LED status display on the control card. With the power on, what is on the display and what color is it?
Are the stepper motors attached to the axis with an open box or tapered cone adapter? Are there Feed Rate and Spindle Speed Override knobs on the front panel of the machine? When the machine was homed, did the axis go up to home position and then go down? Or did the axis just travel very slowly down? Or did they go up and stall against the end of the rail? Does it sound like the stepper motors are turning? Are the threaded lead screws turning? Here is a link to the Sherline website with an exploded view of the lathe, print this out for reference.
http://www.sherline.com/CNClatheX.pdf
If the stepper motor is turning and not the threaded lead screw, the coupler may be loose or broken. The coupler could be loose on the motor shaft (set screw) or on the lead screw (bolted or set screw). If the X axis lead screw is turning, the brass insert nut on the X axis is slipping. It is held in place with a set screw from the bottom of the carriage. The Z stepper motor will have to be removed so that the carriage can be slid of the base rail to get at the set screw. If the Z axis lead screw is turning, then the Z axis nut is not bolted to the carriage. The Home switches may be the problem. Vacuum out around the switches and use compressed air to blow out any debris from around the switches. Try pressing on each switch lever, you should hear/feel a click when the contacts inside the switch open/close. You can check the switches with a volt/ohm meter, set on ohms or continuity. With the switch in normal position the contacts are closed (circuit), when the lever is pressed down the contacts open (no circuit). The switch may have gone bad and needs to be replaced. Also check the wires and connectors that go to the switch, they may be loose, dirty, or the wires are cracked. When the machine goes Home, the axis moves toward the switch, when the switch is pressed and the contacts open the machine moves very slowly (creeps) away from the switch. When the switch closes the machine knows it is at Home and stops. If too much oil was used to lubricate the machine, the oil may have gotten in to the switch and coated the contacts. You can try the “secret home” function to move the axis away from the home switch, see the link viewtopic.php?t=557&highlight=secret
Are the stepper motors attached to the axis with an open box or tapered cone adapter? Are there Feed Rate and Spindle Speed Override knobs on the front panel of the machine? When the machine was homed, did the axis go up to home position and then go down? Or did the axis just travel very slowly down? Or did they go up and stall against the end of the rail? Does it sound like the stepper motors are turning? Are the threaded lead screws turning? Here is a link to the Sherline website with an exploded view of the lathe, print this out for reference.
http://www.sherline.com/CNClatheX.pdf
If the stepper motor is turning and not the threaded lead screw, the coupler may be loose or broken. The coupler could be loose on the motor shaft (set screw) or on the lead screw (bolted or set screw). If the X axis lead screw is turning, the brass insert nut on the X axis is slipping. It is held in place with a set screw from the bottom of the carriage. The Z stepper motor will have to be removed so that the carriage can be slid of the base rail to get at the set screw. If the Z axis lead screw is turning, then the Z axis nut is not bolted to the carriage. The Home switches may be the problem. Vacuum out around the switches and use compressed air to blow out any debris from around the switches. Try pressing on each switch lever, you should hear/feel a click when the contacts inside the switch open/close. You can check the switches with a volt/ohm meter, set on ohms or continuity. With the switch in normal position the contacts are closed (circuit), when the lever is pressed down the contacts open (no circuit). The switch may have gone bad and needs to be replaced. Also check the wires and connectors that go to the switch, they may be loose, dirty, or the wires are cracked. When the machine goes Home, the axis moves toward the switch, when the switch is pressed and the contacts open the machine moves very slowly (creeps) away from the switch. When the switch closes the machine knows it is at Home and stops. If too much oil was used to lubricate the machine, the oil may have gotten in to the switch and coated the contacts. You can try the “secret home” function to move the axis away from the home switch, see the link viewtopic.php?t=557&highlight=secret