Formula 1 Cars - US

[arossner]

I am having problems with two microrouter compacts. I am trying to cut F1 cars (US Design) for students. I can cut 2-3 cars consistently then clear out of the blue it seems that they begin slipping on the Y axis. The car simulates fine on both QuickCAM 3D v3 and in the VR Milling 2d/3d simulation. When I cut the same file on my Compact 1000 I have no trouble.

My Feed Pot is set to run at 100%, I slow things down a bit when we cut the front wing so it doesn't split off the billet. I'm running the stepover at 15% and the cars are set to cut 7mm outside the billet border in the y axis (we do this in QuickCAM 3D v3). Feedrate is 4000 mm/min and spindle speed is 23000 rpm.

Is there something wrong with my Microrouters?

albert.rossner@jcisd.org

[Martin]

What version of VRMilling are you running?

Try updating to the latest version.

If the machine has a NextStep card fitted check & update the Firmware.

Have you lubericated the slides with dry Silicone???

[Benny]

Customer updated software to VR CNC Milling v. 5.20, lubed lead screws, checked e-stop wiring, limit switches and wiring, potentiometers and noticed no improvements. Mentioned to customer that when cutting F1 balsa car blanks the Y axis is doing almost all of the work, pushing and pulling the blank into the cutting tool. The Z axis has to lift the weight of the spindle motor and the X axis steps the Z over the amount of the step-over. If the machine is not maintained, kept cleaned and lubed, the dust and debris will work its way into the bearing races

Customer mentioned that the bearing on leadscrew end is spinning. The bearing should not be spinning in the bearing mount. The bearing may be full of dust and debris, seized, and cannot spin. The torque of the stepper motor is forcing the bearing to turn in its mount, the bearing spinning in the mount creates a lot of heat, and the added strain is stalling the stepper motor causing it to stall and loose position. Recommended that customer will need to disassemble the Y axis lead screw assembly and check/replace the bearing(s). Recommended that customer also check the lead screw for any damage, nicked or bent threads that may cause the lead screw to bind in the threaded joint on the table bracket. Recommended that when the bearings are re-installed, a product like Red Loctite should be used to secure the bearing to the lead screw shaft and bearing mount. The bearing mounts may need to be replaced if they have worn and the bearing is no longer a tight fit.

Customer is frustrated as the state F1 finals are fast approaching. Any other ideas?????

[bradders]

I find it strange that the problem is replicating itself on both Compact machines. I was going to suggest you check to see if the Y axis coupling is securely fastened to both the motor and Y axis lead screw.

Has the customer got a vacuum cleeaner running ? because sometimes a static dischage can interrupt the data communications between the PC and Compact

[boots]

Make sure the cutter flutes are long enough for the depth of cut you are making. If the flutes are too short the shank of the tool will be forced through the wood and stall the Y axis stepper motor causing it to loose position. A flute lenght of 1.5" (37mm) works the best. Or, make two passes in QuickCAM 3D.

[Benny]

Brilliant Boots - thanks! 2 passes set up in QC 3D worked for the customer. Customer had sourced their own cutters and they were not long enough to do a proper job in one pass. The ballnose endmill was going too deep into the balsa and the shank of the tool was being forced through the balsa thus stalling the Y axis stepper motor and causing the machine to lose position in the Y axis. We did not know customer had some cutter burning in the balsa when this all started otherwise the machine disassembly could have been avoided. Although a good cleaning and proper maintenance is never a bad idea!!!!