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CNC Maintenance
This page explains how to go over the different steps for maintaining and using the Shopbot at Fellesverkstedet for keeping the machine in good condition and getting the best milling results. Some of these steps need to be taken care of more often than others.
Jump to:
- Plane sacrificial layer
- Move Z-zero plate down
- Placing new sacrificial layer on top of the machine
- Smear grease on the gears
- Changing spindle RPM
- Routines
- Troubleshooting software issues
- Replace 230V spindle with 380V spindle)
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First step is to move the Z-zero plate down 2 mm, using the white thickness plate and digital angle meter which are found in the red Tengtools cabinet (second last drawer and third last drawer). Use the instructions here if you don't know how to do this.
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Then change the value which controls the distance between the top of the zero plate to "-1". To do this, go on the pc that controls the shopbot to: This PC < OS(C:) < SbParts < XYandZero_Zzero_below_material.sbp Open this file and change the value of parameter "&Zplatecorrection" to -1. (Check this image for reference.)
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Put the Planing bit into the spindle
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Make sure the window and door is closed, and you pressed the reset button to turn on the machine.
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Run the spindle warm-up routine, in case you haven't yet.
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Run the planing file, which will first automatically calibrate the X, Y and Z axis. You can find this in: Dropbox < Fellesverkstedet < Maintenance < Surfacing sacrificial layer < 38 mm planing bit < Surfacing pocket 1mm depth - 38mm Planing Bit.sbp
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When Shopbot asks if your material thickness is 1.00 mm, press ok and start the job.
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The machine will plane the sacrificial layer 1 mm deep so there's no need to change the value again like we had in the old routine.
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Vacuum the sacrificial layer such that the next person can start with a freshly milled flat layer.
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Congratulations, you're done. Now get back to milling!
Since we made an auto-homing plate there's a few steps to go over and make sure that we define the distance correctly between the zeroing plate and the top of the sacrificial layer. On our current setup (November 2019) the following steps will guide you through the planing process:
- First step is to check if there's enough clearance to take away 1 mm on the top, and still have enough distance between the top of the Zeroing plate and the top of the sacrificial layer, after it's milled. To do this, go on the pc that controls the shopbot to: This PC < OS(C:) < SbParts < XYandZero_Zzero_below_material.sbp Open this file and check the value of parameter "&Zplatecorrection". (Check this image for reference.)
If this value is equal to or lower than -1.7 (eg. -1.8), you're safe to take off 1 mm. (Remember: after taking off 1 mm you will need to change this value to -0.7, and since we usually mill down to -0.5 mm in the sacrifial layer, you'll have 0.2 clearance for the sake of being safe) If this value is higher than -1.7 (eg. -1.6), you'll need to lower the Z-zero plate on the side (Press link to go to instructions). Make sure you do this before continuing the following steps, otherwise users might end up unwillingly milling into the aluminium zero plate.
- Put the dovetail milling bit into the spindle (Or if this bit is not available, take a different big bit but make sure you generate a new planing toolpath that matches the specifications of the bit you chose and that it cuts down 1 mm deep)
- Make sure the window and door is closed, and you pressed the reset button to turn on the machine.
- Run the spindle warm-up routine
- Run the planing file, which will first automatically calibrate the X, Y and Z axis. You can find this in: Dropbox < Fellesverkstedet < Maintenance < Surfacing sacrificial layer < 19mm Dovetail bit < Surfacing - 19mm dovetail bit - 1mm deep - autohome.sbp
- When Shopbot asks if your material thickness is 0.00 mm, press ok and start the job.
- The machine will plane the sacrificial layer 1 mm deep in 2 steps: first 0.8 mm deep and then 0.2 mm extra to compensate for thermal expansion happening during the first layer.
- IMPORTANT: After the machine is done planing you go back to the file XYandZero_Zzero_below_material.sbp in the folder: This PC < OS(C:) < SbParts and add 1 to the value inside "&Zplatecorrection". So -1.7 would become -0.7, -3 would become -2, etc... Now save the file with the updated parameter.
- Vacuum the sacrificial layer such that the next person can start with a freshly milled flat layer.
- Congratulations, you're done. Now get back to milling!
- On the side of the aluminium zeroing plate you will find 2 Torx T20 screws that will need to be loosened. Once you loosened these the height of the aluminium plate can be re-positioned.
- Lower the aluminium plate. It's recommended to use a flat piece of acrylic (there's a white piece in the 2nd drawer from the bottom of the tengtools cabinet) or something with a consistent & measurable thickness to help align it parallel to the sacrificial layer. The easiest is to first screw in 1 screw, then use the digital angle finder (can be found in the 3rd bottom drawer from the bottom of the red tengtools cabinet) to level it parallel to the sacrificial layer and then put in the second screw.
- IMPORTANT: After you fixed the aluminium plate to a lower height you go to the computer and open the file XYandZero_Zzero_below_material.sbp in the folder: This PC < OS(C:) < SbParts. Here, you need to change the value of &Zplatecorrection to the new depth according to the sacrificial layer. If you used a flat piece to help align it parallel you can measure the thickness of that piece and enter that value (Remember to use "-" if your aluminium plate is below the sacrificial layer). If you didn't use a flat piece you can measure using calipers the distance between the top of the aluminium plate and the top of the sacrificial layer.
- Now save the file with the updated parameter and you are ready to run the plane the sacrificial layer, as described above here.
Placing a new sacrificial layer on top of the shopbot (ca. 2.5 hours + drying time & 1 hour for planing the day after)
When the sacrificial layer gets too thin (<20mm) it's important to glue on a new top layer. This is to prevent screws from making drilling holes into the plywood base layer when screwing down material onto the machine. We use HDF as a top layer for cutting into. Mdf would probably be cheaper but it would not last as long for screwing into. IMPORTANT: Make sure there's enough time to go through the process (ideally a free afternoon on the shopbot and 1-1.5 hour free in the morning the day after to plane the machine flat again.)
Steps to take to glue the top layer:
- Plane the sacrificial layer flat using the instructions written above.
- Vacuum the sacrificial layer such that there's no more dust on the machine
- Place the new layer on top of the freshly planed machine
- Pre-drill holes into the new layer which we will use to screw down the new layer after applying glue. To do this, you put a 4 mm drill bit into the spindle and run the job "Borrjobb offerplate - 4mm drill - med autohome.sbp" from the folder Dropbox > Fellesverkstedet > Maintenance > Borrejobb offerplate.
- Remove the new layer from the machine again, but position it not too far from the machine as you will need to be quick after glueing.
- Use the gluing tool to apply enough glue on the planed layer of the machine. Careful, here you will need to act fast as the glue will harden quickly. Before applying the glue you might already give 2 friends heads up that you will need help putting the new layer on. Also, don't underestimate how much glue you will need.
- Position the new sacrificial layer on top together with your friends and screw it on the machine using the pre-drilled holes.
- Let it dry for 12 hours
- Move the Zero plate up using instructions written above.
- Plane the sacrificial layer one more time flat using the instructions written above.. Instead of milling 1 mm off the top layer you could try doing 0.5 mm (or even 0.3 mm if that's enough to remove a tiny bit of the top layer every where on the new sheet).
- You're done. Have a coffee, you deserved it.
Take the multi-purpose lithium grease (Laying in the lowest drawer of the red TengTools cabinet - April 2020) and a small scrap piece (maybe time for a dedicated brush?) to spread it on the axes (X+Y). Scoop tiny bits of grease and apply it to the axis, about 15 cm apart. Make sure to also move the bridge so you have access to apply the grease to all parts of the axes. You get bonus karma points for removing the overflow of grease after running the machine for a while, which makes sure it's less easy to get grease on your clothes when f.e. screwing down pieces.
For the z-axis, the instructions still need to be written down.
With the current setup (Nov 2019), the machine turns completely off when you either open the window or open the door. From earlier tests and jobs we've run, we've experienced you get a difference in squareness depending on where the machines get turned on (up to a millimeter difference). This can cause issues for projects, as the different jobs being run (pockets/drills/cuts) might end up in a different position. To make sure you repeat the best squareness of the machine it's strongly advised to pull back the machine to the physical end stops on the front of the machine, every time the machine has been turned off and on again. Take the following steps for doing this:
- Close the window and door to the machine room and make sure to press the reset button for starting the machine.
- Press first "C" and then "Change tool" so that the machine automatically moves into the tool change position which is in the front of the machine.
- When the machine stopped moving, open the window again and pull the bridge slowly closer to the front until you cannot move it closer. When done pulling, close the window again and remember to press the reset button.
- Now you're good to start milling. Remember to do this step every time you turn off the machine by opening the door or window.
On both sides of the spindle is a V-shaped track (dovetail) which makes sure the spindle slide up and down straight. These will need to be cleaned using WD-40
- Move spindle all the way up to reach on the top of the track and all the way down to reach at the bottom
- Spray WD-40 and use scotchbride pads to help rub of debris
- Use paper towel/cloth to remove remaining debris
The V rails are the small triangular rails on top of the aluminium profiles where the bridge runs on in the X and on top and bottom of the bridge in the Y direction. These will need to be cleaned using WD-40 to avoid any clogging of debris. Process is fairly straight forward:
- Spray WD-40 on rail
- Wipe with cloth until all debris is cleared from the rails
If the pinion is not properly engaged in the rack, the machine can get a slack while cutting which means you loose precision on the machine. To avoid this problem, the pinion needs to be regularly checked for engagement. To check for slack you'll need a friend that can turn on the machine while you are in the room and if necessary help with retightening the pinion onto the rack.
- Go into the room and close the door and window.
- Have your friend press the reset button to turn on the machine
- Try moving the bridge back and forward in the X-axis. Do the same test with the spindle assembly on the Y-axis. If you can make the bridge/spindle assembly move it means that the pinion is not fully engaged in the rack so you'll need to fix this. To do that, continue with the steps below. If there's no slack on the bridge you're done
- Loosen the machine screws (4 per pinion), located around the motor.
- Have your friend pull the motor towards the rack while you retighten the machine screws.
- Done!
The retrofitted 400V VFDs on the Fellesverkstedet shopbots currently does not have digital spindle control. Any spindle speed set in v-carve or other cam software will be ignored. The VFDs are currently manually set to 18000 RPM. To change the RPM:
- Enter the shopbot room and get someone to press the safety reset button once you have closed the door behind you
- Press and hold the "Navigate key" on the VFD controll panel for 2 seconds (the top middle button)
- Browse to parameter "P-02" with arrow up/down
- Press the "Navigate key" key to select the parameter
- Use the arrow keys to reduce the RPM setting
- Press the "Navigate key" to confirm new settings
- Press and hold the "Navigate key" for 2 seconds to leave the menu
- When the project is done, don't forget to set the RPM back to our default 18000!
More info on programming the VFDs can be found in the Invertek Optidrive E3 manual in the Fellesverkstedet machine manual library. Digital spindle speed control is planned to be introduced in connection with upgrading the machine control electronics (probably to GRBL).
These routines have been based on Shopbot's recommendations and have been rescheduled based on estimated running time of the machine. Shopbot's recommendations (downloaded 16.09.20) can be found here.
Before milling:
- Warm up spindle using the warm up routine in the shopbot software (Shortcut C5 on keyboard)
- Check chuck and collet to make sure there's no dust or debris when inserting milling bit
- Check if correct dust extraction is connected to machine
After milling:
- Tidy up
- Plane sacrificial layer if necessary
- Clean rack and re-grease with multi purpose lithium grease (in the red Tengtools station).
- Clean the V rails on X and Y axis
- Check if there's no slack on motors and if necessary retighten them close to the rack
- Clean the V Bearing edges of Z assembly
- Check felt pads on V-rail and replace if necessary
- With motors removed, or at least disengaged from the racks, move each axis through the full extent of motion and check for looseness or binding.
- With motors removed, spin test each of the V rollers on the X and Y cars for free movement
- Tighten all pinion set screws. Check for signs of movement. Replace pinions and damaged key stock (if present) if movement was apparent.
- Using provided flat wrench, adjust V roller bearing eccentrics on Z axis.
- Remove lower YZ car V roller dust covers and adjust eccentrics
- Remove, clean, inspect, reassemble, lube and adjust complete Z extrusion assembly.
- Update software and firmware.
- Plane down to plywood layer and put new layer of Valchromat on top.
- Replace all pinions.
Sometimes the shopbot software has issues. Here is a list of troubleshooting options to follow.
- Reset Computer
- Run software as Administrator.
- Check Region setting on windows, this needs be set as region USA and region format as English (United States), this can accidentally be reset by a system update.
- Check if the USB is connected or has an issue. Disconnect the USB then run software in preview mode to see if any issues remain. This will show if the issue is to do with the USB connection.
- If issues persist, open Shopbot3 and go to [U]tilities - [R]eset default settings.
- Reinstall latest ShopBot Software, https://www.shopbottools.com/support/control-software. Make a copy of current settings(OS(C:)/SbParts/Custom), (set_Z_zero_to_top_of_material.Sbp) and (XYandZzero_Zzero_bellow_material.sbp) onto the desktop. These are the main settings for the shopbot. Run the installer. When finished, copy original settings into SbParts folder.
- Finally, copy settings from the other shopbot. Remember to keep the original (set_Z_zero_to_top_of_material.Sbp) and (XYandZzero_Zzero_bellow_material.sbp) this is sepcific to each BOT and can cause issues for Z axis zeroing.
As a result of moving to our new facitilies at Seilduksgata we've had to change the vfd to be able to run on 380V instead of 230V. The new VFD was not supporting the specs to run the old spindle optimal (the spindle would stop quickly when it would get too much torque) so we got a new spindle that supports 380V. Below is documentation on the steps taken to replace the spindle.
Tools needed:
- Umbraco
- Tools for removing the dust extraction
- Loctite glue for screws (normal, not strong)
- Thin flathead scewdriver for unplugging cable to fan
- 90 degree angle square
Remove Old spindle
- Move bridge with spindle all the way to the back, so we get access to the bolts for removing the spindle later
- Unplug machine for safety
- Remove cables connected to spindle (orange for the spindle and the gray for the spindle fan)
- Remove dustskirt to get access to the back of the slide where the spindle sits on
- Remove the 6 bolts that connect the bridge to the aluminium adapter plate (it's the aluminium plate between the z-axis and the spindle). Best is to start with the top 2, because you'll need to push the spindle lower than the sacrificial layer. Then you can put the spindle again above the sacrificial layer when your remove the other 4. Make sure there's somebody to help hold the Axis down and prevent the spindle from falling when the last bolts are loosened.
- The spindle with the aluminium adapter plate is now loose. Now you can take out the 4 bolts connecting the adapter plate to the spindle.
- Now the spindle is loose and ready to throw/sell/repurpose
Install new spindle
- Clean up the bolts using a messing brush
- Attach the adapter plate in he right direction to the new spindle: Use loctite glue for machine screws (not the one that's hard to remove) and apply a drop on each bolt before screwing.
- Place the spindle with adapter plate straight on the sacrificial layer in front of the z-axus and have somebody help you push the Z-slide down such that you can **loosely ** attach the spindle with adapter plate to the Z-axis using the bolts. Then use the angle square against the sides of the spindle before tightening the bolts, to make sure the spindle is 90 degrees to the sacrifical layer.
- Connect the spindle to electricity again (orange for the spindle and the gray for the spindle fan)
- Attach dust extraction to machine again
- Now the electricity to the shopbot can be connected again but the VFD will need to be reprogrammed for the settings of the new spindle:
Program VFD By programming the vfd we need to enter the settings so that they match the specifications on the spindle (specs are on the gray sticker on the front). The vfd has a lot of parameters that can be changed but the important once for replacing the spindle are P-07 - Parameter 7 (Motor rated voltage), P-08
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Parameter 8 (Motor Rated Current), P-09 - Parameter 9 (Motor Rated Frequency), P-10 - Parameter 10 (Motor Rated Speed). To change these settings, follow these steps:
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The machine will need to be turned on while you are next to the vfd (so at Fellesverkstedet you'll need somebody to press the reset button while you are in the room)
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Press and hold the "Navigate key" on the VFD controll panel for 2 seconds (the top middle button)
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Browse to parameter you want to change with arrow up/down.
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Press the "Navigate key" key to select the parameter
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Use the arrow keys to change the value to the correct value read from the spindle.
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Press the "Navigate key" to confirm new settings
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Press and hold the "Navigate key" for 2 seconds to leave the menu
More info on programming the different parameters of the VFD can be found in the Invertek Optidrive E3 manual in the Fellesverkstedet machine manual library.