As the middle of July approaches MechArtisan continues to push forward with Thermwood CNC router revisions as well as some intense CNC machining operations. In addition, the team has been pursuing some very interesting projects in a number of different sectors both within Maine as well as in the greater Northeast. With the pursuit of these opportunities we have been fostering new relationships with complimenting material and support providers around the state and have been pleasantly surprised by the amount and quality of resources we have within the Southern Maine region.
The Thermwood control has been stripped out in its' entirety. We were able to find buyers for the old Perske router spindle as well as a number of the internal controller components.
During dis-assembly we discovered evidence of past machine abuse which wasn't disclosed by the seller. This is always a bit irritating but luckily the damage was limited to components which we were planning on replacing anyway. The Z axis actuation was wrecked with two blown linear bearings and a severely overloaded and bent ball screw assembly. We also found the ball dual ball nut in the Y axis linear drive is severely worn and will require some new recirculating chrome steel balls. On the positive side, all 3 Baldor 2.5kW (3.3hp!) servo motors are in very good condition and were recently retrofitted with new 600 count encoders. The encoder counts may prove a bit light for our precision requirements but we're going to run them first before making a decision to upgrade.
Mick has been busy designing our new extended travel Z axis which will take us from 5" of Z travel to 12". In addition to the actuation redesign, we will be adding 8" riser blocks to the gantry to allow 20" of clearance. We are beginning to assemble parts and are hoping to dig into controls within the next 2 weeks.
Aside from router revisions we have also been doing some complex 3D mold machining for a client. The project began with some 3D CAD model issues which we helped to resolve and then we spent a considerable amount of time perfecting the CNC code to optimize tool paths and provide the best surface finish possible. The entire component is manufactured from a single piece of 2.5"x 4.5"x 12" Aluminum 6061-T6 billet which begins weighing just over 13 lbs.
After approximately 170,000 lines of CNC "G Code" has run down the screen, we end up with this...
And of course, this....
The finished component is then polished by hand. The 13lb block of aluminum now weighs 2 lbs. Initially the CNC code took 7 hours to run but after a significant amount of optimization we are now producing finished components off of the CNC mill in 4 hours and 10 minutes. This particular project has pushed us to improve our CAM programming abilities as well as explore the intricacies of high speed aluminum machining. Our primary cnc mill is limited by its' 3 hp 5000 RPM spindle but we are still able to manage a material removal rate of just under 3 cubic inches per minute. This new level of understand both of the programming involved in efficient material removal as well as the correct tooling selection to affect that removal is exciting and will be of great benefit as we quote complex cnc machining work in the future.
In the coming weeks we hope to see significant progress on the Thermwood and will be sure to keep our blog followers up to speed when it starts coming together.