So I’ve reached an Impasse. I really want my kickstarter ready before Maker faire, but I also have a couple of machine tweaks I want to make before Maker Faire. I don’t think that I can accomplish both. Here’s the design changes I’d like to finish before Maker Faire:
- Extruder change. I’m currently installing a new hot-end, to get a reliable .35mm extrusion. Right now, I have a mildly broken .50 hot end that has worn to .69. With this change, I think I can hit Replicator or better print quality. The only thing stopping me before was my hot end. I’ve also designed a new cabling system for the extruder/hot end/thermsistor, that I’m testing at the same time as this change. It allows use of CAT-6e 550MHz ethernet cable. Why Cat-6e 550MHz cable? It’s usually 23 AWG solid core. Cat-5 is 24AWG, usually. I’m hunting an easy cable that has 6 or more conductors, can be bought cheaply pre-made, has a positive-lock and keyed connector, has some sort of screw-terminal protoboard, and is at least 23 AWG stranded wire for each conductor. Ethernet has almost all of these, except the stranded wire. I’m willing to test it and see how it goes. I f*ng hate building cables. The BLS connectors and pin header used on RAMPS really pisses me off. I’ve lost 3-4 days of time on those connectors, sleeves, etc…
- Belt path change. This will increase the usable Y space during printing in fixed gantry mode.
- Adding a second Y motor. This will allow milling of tougher materials. I don’t think I can pull this off — I have the motor and parts, but I don’t have the time needed to re-wire for this change. This likely won’t make it to Maker Faire.
- Getting some samples made. I’ve only got today and tomorrow left, and then only the evenings after work.
- Electronics. This is bothering me to no end. I love the 5 stepper configuration of RAMPS. I HATE the pin header connectors. I love and hate the Allegro stepper drives. ( Love them — good current. Hate them — overheat. ) I want to allow dual extruders on the final version, as well as a bowden system. That can only be done with RAMPS. But I don’t want people building cables. RAMPS is also very expensive! To fix all the problems I see, I may have to design my own board around a stepper logic driver. But I want to ship this year. So, I’ll probably live with the cost, and design a case for RAMPS with an integrated fan, as well as fixed-position connectors on both the case and on the machine. This way, people only plug-in the “moving” part of the cable.
Other than than, I’m contemplating some additional changes to the design:
- Moving to BallScrews. This is tough one — I like belts, and using belts means good safety. Right now, bad GCode ( as in crashing the mill head into something or other mistake ), using a 1/8″ endmill, stalls the Proxxon ( it’s only a 40 watt tool ), and stalls the motion axis where the mistake happened. It’s noisy and scary — but doesn’t do any real damage. I like this — it makes the mill inherently safe. You just can’t do something stupid enough to damage yourself or the machine. Worst case, you damage the part you’re working on. Great! But, it has a downside as well. I’d like to get to mild steel, and the current motor/belt/router configuration will probably stop at plate aluminum. Belt is very accurate and has little lash. I want to keep those characteristics if I move to screw. BallScrew meets all the requirements, but is expensive as hell. Even a cheap ballscrew means an expensive, and large, ball nut. And talk about your mounts! Woo! You can literally double the price of the entire machine for a single ballscrew, nut, and mounts! I’d have to find a great supplier, or design my own mounts to make this an affordable option. But it would allow Jewelry-level work, so it could be worth it. I could also use fast travel ACME. But that eats 50% of the motor power.
- XZ plate changes, gantry height changes. This would allow printer mode to be more space efficient, if I add 2 more MakerSlide wheels in the middle of the plate. It could then extend it’s reach another 1.5 inches. I have unused space at the top of the MakerSlide Z beam in print mode. But these changes would make it no longer fit in the trunk of my car. I think keeping it “trunk-able” is important, so I’m mulling over this change. EasyMaker can already over-flow its frame, both in milling and in printing, so I’m not sure this is an important change. But the software, ooh man — that’ll be a massive change to handle printing via overflow.