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How to use the Shopbot

Shopbot instructions

Before you are allowed to operate the Shopbot you have to have had safety instructions and made your own documentation on the use of this machine. Some general notes before use:

  • The spindle can make up to 18000 rotations per minute which is DANGEROUS. Be extremely cautious with the placement of the bolts in the material because when you bump into metal with the mill it will generate sparks. In combination with sawdust there is the risk of fire or even explosion. Check everything you are doing constantly. A safety measure is to add the positions for the screwholes in your VCarve file and run those toolpaths first.
  • NEVER LEAVE THE MACHINE WHILE IT’S RUNNING!

Steps

Open the Shopbot software before turning on the machine, otherwise there is no connection. Make sure that you’re not randomly pressing keys on the keyboard as a lot of keys correspond to commands to the Shopbot. After entering the keypad (shortcut is k) you can move the mill with the arrows in the keypad or the left arrow, right arrow, pgDown and pgUp.

1. Preparing your material

  • Clean the sacrificial layer and sand if necessary (mostly bumps where screws have been taken out) so the bed is level.
  • Screw the material to the sacrificial layer, taking your file into account with the placement of the screws.
    • When working with bigger plates of wood, you should make a separate toolpath for the screwholes and run that first.
    • When using foam, add double sided tape to the bottom of the material and stick it to the bed. Use two wooden beams to create a perpendicular angle, place the foam and use two more beams pressed right against the foam to secure the foam. This is because when it’s just taped the foam may come loose, ruining the whole model.
  • Check if the vacuum bag is properly attached, and whether the correct one is attached: we have one for foam and one for wood.

2. Changing the milling bit

In the drawers you can find the mills for the Shopbot. Always put the mill back in the correct drawer after use.

Lower the skirt by loosening the butterfly nut at the back of the machine head. Then grab the collet, nut and milling bit. Make sure you have the correct diameter collet for the mill that you’re using; double check with caliper.

First put the collet in the nut (you have to feel a click), then the milling bit in the collet. In the pictures below you can see the collet loose in the nut on the left and properly secured on the right.

Make sure the milling bit is put in until where the collet stops touching the milling bit on the inside. Measure how much the milling bit is sticking out and keep this value in mind, make sure you’re not milling deeper than that.

Unless you’re milling in a pocket and know what you’re doing, you have the risk of bumping into your material with the machine head like below.

Then tighten the nut to the machine head using the wrench and plier. Put the skirt back.

3. Zeroing the axes

First you have to zero the X and Y axes. Start with zeroing the machine with the Zero X/Y button so the machine looks for it’s absolute 0,0 point. Note that it’s not Jog home, the 0,0 button; that one will make the machine go to the last home position. Then move the machine to the X,Y position that you want to use as your zero position, take a picture of the X and Y position displayed in the menu, exit the keypad and press 2 (or click on the tab Zero > Zero X and Y axes). You need the picture because if for some reason the machine has to stop or the software crashes while milling, you can still continue with your file; otherwise the machine does not know where to start because setting the X,Y position sets it to 0,0.

Before zeroing the Z axis, test if the milling bit and metal tool form a connection. If they do the light under output 1 in the Position window turns green. If the light doesn’t turn green, check if the alligator clip is connected to the machine head, and check if the milling bit and metal plate are free of dust. You can zero the Z axis on top of the material or on the sacrificial layer, this depends on what you specified in VCarve so make sure it corresponds to that. Move the machine head to the center of the material or to a good spot on the sacrificial layer, put the metal plate under the mill and press the zero Z button. The machine will stop moving down as soon as it touches the metal. The tool is 3.070mm thick so that is where it will stop. If the end mill doesn’t go up after zeroing automatically, you have to open the keypad by pressing K and press pgUp and ONLY pgUP before you start moving the X and Y axes or you’ll destroy the machine/mill/tool.

4. Starting the job

Now load the partfile (don’t change anything in the file).

Turn on the power of the dust collector (switch in the back of the room, lamp turns green when it’s on), press the red button on the front of the machine to turn on the dust collector and use the knob to increase or decrease the power. Then turn on the spindle by turning the key in the keyhole next to the on/off switch of the Shopbot. This is a great moment to have a look at the milling bit and to check whether it’s ‘dancing’: this is what happens when the collet hasn’t been put into the nut securely.

The spindle speed can be adjusted with the buttons on the box below the machine. If you’ve set the speed in your file it will go up or down to the specified speed, but it’s always good to check.

Now press start to start the job. Keep your hand on the space bar for the first few minutes of milling: pressing the space bar pauses the milling job (note that it doesn’t stop the spindle from rotating) while watching if everything is going well and as expected.

General notes
  • If you want to pause the job, it’s best to do this while the machine is making a travel move and not while it’s milling in the material. If there’s no other way, stop the spindle right after pausing the machine
Notes on dust collection
  • If you notice that the dust collection isn’t working properly (a lot of sawdust stays on the material), check whether the tube is clogged with sawdust. Since it’s connected with duct tape to the machine head, sometimes dust gets stuck between the tape and the tube
  • Don’t turn on the dust collection when milling wax, we’re reusing the wax
  • When switching between wood and foam milling, switch the bags in the dust collection room. Make sure the belt connecting the extractor to the bag fully wraps around the bag, otherwise you risk dust getting everywhere and you have to clean up the mess you made