Fab@Home:Model 1 Commissioning

Step 1: Position the machine with the rear facing you, and have the timing belt and your Allen wrenches handy.

Step 2: Ensure that the right-hand (X motor side) timing pulley is positioned as shown, with the wave-spring washer compressed between the pulley and the bearing, and that the pulley hub is securely tightened. Turn the pulley back and forth by a single turn - it should turn smoothly, and you should see the XY Carriage move slightly as well.

Step 3: Slightly loosen the two #8 screws which secure the belt tensioner until you can slide the belt tensioner up and down. Also loosen the left-hand timing pulley so that it will slide easily off of the shaft.

Step 4: Lay the timing belt around the right-hand pully and belt tensioner pulley.

Step 5: Slide the left-hand timing pulley off of its shaft, being careful to leave the spring washers on the shaft. Loop the timing belt around the pulley, and slide it back onto the shaft.

Step 6: By turning the motor shafts by hand, maneuver the XY Carriage so that the Y Carriage is at the left/right center, and very near to the rear of the machine (closest to you).

Step 7: Without rotating the belt or any of the pulleys, and without, turn just the left-hand X shaft until the back of the Y Carriage (for instance, the rear surface of the bearing pillow blocks) are parallel to the nearest edge of the top of the Machine Base.

Step 8: Carefully tighten the left hand timing pulley without rotating the shaft or the belt, remembering to squeeze the pulley against the bearing to preload the wave spring washer.

Step 9: Now reposition the shaft collar at the front of the left-hand X shaft to ensure that the left-hand X shaft does not have any axial play. Loosen the shaft collar, pull the shaft toward the front of the machine, squeeze the shaft collar against the bearing (recompressing the wave spring washer between the pulley and the bearing at the rear of the machine), and retighten the shaft collar.

Step 10: Slide the belt tensioner downward until the belt can easily be deflected only about 1/2" up or down - the belt should deflect upward to roughly the bottom edge of the joint between the rear and top surfaces of the machine base. Secure the belt tensioner screws to keep it at the correct tension. Too little tension will let the belt slip over the pulleys, too much tension will bend the X axis shafts and cause premature wear of parts.

Step 1: With the rear of the machine facing you, ensure that all of the #8 screws which secure the X rail flange mounts to the machine base are loose.

Step 2: By pulling on the timing belt, drive the XY carriage all of the way to the front of the machine then all of the way to the back, being careful to not force the carriage against the limit switches - just stop when you hear the limit switches click.

Step 3: Now gently tighten the #8 screws on the right front X rail flange mount.

Step 4: Repeat steps 2 and 3 for each of the other 3 X rail flange mounts, beginning with the right rear. When you are done, you should be able to drive the XY carriage smoothly from one end to the other of its range of motion with little force on the belt. If you notice a change in force at one end of the range of motion, repeat the above steps.

The Xylotex 4-Axis amplifier has testpoints and potentiometers (adjustable resistors) that you can use to measure and adjust (respectively) the current delivered to each motor. When you receive the board from the manufacturer, the currents will typically be set much too low for the motors used in the Model 1.

To measure the current, set your multi-meter to read DC Volts, and ground your meter to the negative (white) power supply terminal and probe the labeled test points on the board. Here you see the testpoint for the X-axis being probed.

Use a Philips screwdriver to turn the potentiometer (blue) to adjust the current.

For each axis, adjust the potentiometer until the voltage you read roughly matches the value listed for that axis in the table above. Remember that the voltage you read from your multi-meter is not equal to the current delivered to the motor - you need to divide the voltage value by 1.44 to calculate the current.

Step 1: Insert a syringe with a needle/nozzle attached into the 1-Syringe Tool. To do this, manually turn the syringe tool motor shaft until the tip of the shaft is almost flush to the motor body. The top of the syringe should be tipped toward the tool body, lifted as high as possible, then the tip can be tilted toward the body, snapped into place, and slid downward until the bottom of the syringe barrel is resting on the bottom plate of the tool body.

Step 2: By manually turning the Z-axis motor shaft with your hand, adjust the height of the table until it touches the tip of the syringe.

Step 3: By pulling on the X-axis belt and manually turning the Y-axis motor shaft, drive the tip of the syringe to the four corners of the table, while observing the clearance between the tip and the table.

Step 4:Adjust the (five) table leveling screws to change the height of the table where necessary so that the tip clearance from the table remains constant as you move the tip around the four corners and center of the table.