In this step I mount the auger drive motor, it has a built in right angle drive and speed reducer which adds torque. The motor comes complete ready for wiring and mounting using four screws. Again I drew up the parts in SketchUp and then cut them out on the CNC plasma cutter, it was almost too easy. The further I get down this path the more I take advantage of the CNC’s capabilities. Note the rounded corners, I also added an extra hole on top of the motor mount plate to make adding a wire routing clip easier in the future. I remade the worm drive plate to improve some of the adjustment capabilities and added at the same time some decoration, rounded corners and used less material.
I used a Lovejoy type shaft connector to connect the motor to the worm shaft with a Buna-N spider in between to minimize any vibration or backlash to the motor, although with the worm and worm gear combination there should be none.
This step was made simple by the use of the CNC plasma cutter to make a part which I then bent up on both ends using my homemade brake. But first let’s revisit the old configuration for comparison.
I had to rob the motor and some parts from this transmission so it is in disarray but you get the idea of the complexity. It requires four sprockets, two chains, a motor and two chain tensioners. Here is a picture of the newly implemented and untested solution for mounting the worm and worm gear.
The CNC made it easy to slot the holes for adjustment, so the vertical adjustment comes from the plate to plate mounting screws, and the bearing mounting holes are slotted to get correct in and out adjustment to the keyed worm. After cutting the part and mounting it I decided what to change in the next iteration. I modified the part to round all the corners so that there are no sharp edges and extended the plate to pick up a second set of holes so the plates are attached with four screws instead of two. I think this part is perfectly functional so I won’t implement the changes but at least the SketchUp drawing has been updated.
Notice the title didn’t say completely finished since the last few steps are to improve the acme screw feed as well as add a water table, ventilation system and wire up a better connector for the torch control. But the paint looks great and the electrical components in a box is great. The part you see cut is intended to be the plate that is the interface between the boiler and the burner. I call it the burn plate. It will go into the opening in the boiler, the holes in the very bottom will allow a resistance heater to light the biomass either pellets or chips, the holes above are for draft. The large hole in the top center is for the auger feed and the remaining holes are on the left, a fire detector sensor and a hole to be tapped for attaching the sensor. The two holes in the upper right are intended to be the swivel point and observation port to observe the flame. I drew the part that you see pictured up in Google Sketch Up. What really impressed me about Sheetcam is that the piece to swing and hide the flame in the observation port was made at the same time from the scrap that was cut out of the auger hole. Sheetcam automatically figured out the hole in this swinging part should be cut as a hole with the offset of the kerf to be on the inside of the hole, then cut the remaining profile as a outside kerf, then cut the auger hole as an inside hole. This was all done in the correct order automatically. Cool! Sheetcam is a great program.
The plasma cutter is working in the CNC mode! I have successfully cut parts that meet dimensions and are usable. I made the plates that mate with the casters for the bottom of the machine this morning. I have them welded on and working. It was a treat bolting them together with no alignment issues without spending the time to make them on the Bridgeport.
The CNC is not finished, I have to mount the cable tracks, as well as extend some of the stepper motor wires to allow the full movement of the machine. Before I move on I want to put a coat of paint on the steel parts to make it look finished and professional. But an important milestone has been reached. This machine will allow me to make parts designed on the computer as well as improve the quality of the chip boiler parts significantly. This week I intend to finish the CNC and rebuild the hoppers support wheels. More pictures when I finish the CNC.
After assembling all the lead screw nut to carriage connections the machine is testable. I ran a program supplied with Linux Enhanced Machine Controller that required coordinated motion between the axes. This came out in an interesting way, mirror image. I figured out that the y axis was opposite from the expected direction, or in other words, when the program called for a positive y axis move, the machine delivered a negative y axis move and vice versa. This was a simple fix, I physically picked up the axis and moved it end for end with a helper and remounted it. After that the test program ran just fine.
Image with corrected axis, you can see a little of the same program showing the E in the correct orientation, as well as a 5″ x 5″ box program that I was able to import from StepCam, although I did have to edit the program to get it to run.
Next on the CNC list is to order some additional materials from McMaster-Carr to finish the Z axis as well as some electrical routing accessories to finish the limit switch installations. Last but not least I will need to improve the mounting of the sharpie, plasma cutter and whatever other option should be available for this machine. No doubt a router head would be useful as well. I have the material for the fabrication of a base so I will start on that this coming week as well. Of course this is not the only thing on my list, I still have to make a living so progress will be measured in hours. Thanks for reading, and tell your friends.