I recently got a Shapeoko 4 XXL on the second hand market. It seems to work fine. I did some mistake during projects test and heard some scary noise, but read on internet that it’s common to make mistake and hard to destroy thoses machines.
On my last projects I figure out that my circle wasn’t totaly perfect, I think it was my speed, feed rate and passes that was adequates for the wood. But I also realize that the MDF wood was wrapped and decided today to clean the machine a little and follow some tutorial online to “tune it up” and give it a nice cleaning.
I haven’t started much that I’m already facing some questions. Since I didn’t bough it new and build it myself I don’t know what to expect or not.
The left X axis seems to be able to push few milimeter further than on the right.
But the most worriesomes for now is the y axis moving mechanism that do make a weird statter noise when I move it by hand wile the machine is off.
Power down and remove both Y-axis belts, then put a bit of tape on the pulleys (so as to more easily see their rotation), then power up and connect to the machine and try to initialize — it should home the Z-axis as normal, then try to move both X- and Y-axes, the X-axis should also home as normal, while the Y-axis should rotate until they time out — do the two motors turn evenly and in synch?
With an SO4 it is belt driven. Power off the Shapeoko and move the gantry back to front and side to side. Do this slowly or you get EMF feedback from the stepper motors. The gantry should be easy to move in all directions. If you encounter rough spots check your v-wheel adjustments at the bottom of both ends of the gantry and at the bottom of the Z axis. As @WillAdams suggested taking the belts off inspect them for any missing teeth or what looks like stretched belts. Replace the belts if you find either. Lastly the stepper motor pulleys have two set screws in each pulley. Make sure one of the set screws are on the flat of the stepper motor shaft. If they are on the flat and tight then put a magic marker across the center of the pulley. This is to see instantly if a pulley is out of sync in the future.
The v-wheels are on eccentrics. Loosen the bolt and use a wrench to adjust the v-wheel until it feels like a good fit. Then hold the wrench in place while you tighten the bolt. If you dont hold the wrench in place the tightening of the bolt will turn the eccentric out of adjustment. With the Shapeoko off push on each v-wheel on the bottom and it should move the gantry. Do not over tighten them but have them so they can move the gantry. You might want to examine the v-wheels to see if they are cracked or distorted. If you take the eccentric v-wheels off there is a washer between the frame and the v-wheel. Since this is a used machine be sure to put it back on or the v-wheel will rub on the frame and not move properly.
Belt driven machines like the SO4 should move easily with no tight spots. If it does not move smoothly it will show up when running projects with circles that are ovals. If all you mechanics are in good shape there is an additional procedure to calibrate your machine by changing the steps per MM in the firmware. That is rare and is usually a mechanical problem. Just move your Shapeoko slowly or you will hear something that sounds like the belt slipping. Just slow down to avoid the electro magnetic force feeding back from the stepper motors.
I will try thoses, I didn’t knew about EMF, I hope I didn’t made anything wrong !
How to change the firmware to mm ? I actually only use mm for my projects anyway.
I will try to figure out all the procedure you and @WillAdams have proposed and see where it goes.
Stepper motors are moved by shift magnets. So a deenergized stepper motor if spun fast enough will create its own field and that is why you feel resistance when moving the gantry too fast. Unless you repeatedly create emf it is unlikely to cause any problems. When you do generate emf it feeds back to the controller driver. So extended emf could theoretically cause damage to the driver circuits. That is unlikely when just doing it occasionally or for a few seconds.
The main emphasis is moving the gantry front to back and side to side to see if you encounter any hard spots. If you find consistently a hard spot fix that before moving on to other fixes. The gantry should move smoothly and easily in all directions.
The Z is a little harder. The SO4 came with a Z-Plus but could be upgraded to an HDZ. You can twist the lead screw on the Z-Plus and can be a little hard to get a good grip. It has oil on it and is hard to get your fingers in there. You can however move the top to bottom and bottom to top with a little effort. The Z-Plus and HDZ need to be lubricated periodically with Mobil Vactra #2 oil. It is sometimes refereed to way oil. C3D sells maintenance kits that have a small bottle in it. It does require you to remove the Z to lubricate the lower bearings. There is a small screw you remove and squirt the oil inside. You can also just rub oil on the guides and get some lubrication inside to the ball bearings. The prescribed procedure is found in the maintenance manual.
