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I owned a 3020 and own a Shapeoko 2. Unfortunately, I rarely use them. The biggest problem with CNC is that the overhead is so expensive. There's very little ro

I owned a 3020 and own a Shapeoko 2. Unfortunately, I rarely use them. The biggest problem with CNC is that the overhead is so expensive. There's very little room for mistakes and material cost (stock and bits) can get very expensive. Holding a part can get tricky and the wrong feedrate can ruin your part. I end up using my 3D printers to do most of my parts nowadays. Though I do use my CNC for "food grade" stuff around the house.

NegativeK 8y ago
This is largely the difference between hardware projects (not just electronics -- metal and wood as well) and software. Decent quality physical things and materials can't be downloaded and reused indefinitely.
yourapostasy 8y ago
> ...and material cost (stock and bits) can get very expensive. I've been looking at CNC for a long time, and I've read that if you're starting from scratch, to allocate about the same amount that you spend on the mill itself to the consumables/logistical tail (end mills, cutting fluid, ancillary metalworking tools). Due to the steady degradation of quality design and manufacturing, and rapid support obsolescence, there is an endless supply of improvements I could make around the house if I had enough time and equipment. It bothers me greatly to hear from appliance repair techs that I must throw out an entire major appliance instead of repairing just the pieces that broke [1], because the parts are either grossly expensive, or even simply not available. I'd love to own "versioned, open source" appliances, where open specifications let everyone repair only what breaks. And when something breaks, the community can figure out the root cause and redesign for greater robustness. Like if a plastic part wears down causing a cam to miss a gear, then redesign to machine the cam out of high strength steel. Or if lots of people note a design oversight that makes a particular maintenance procedure a pain, a different access panel is designed and distributed for machining. Or if someone wants upgrade to a later version of an appliance, they swap out only the guts that change, and not the entire assembly, ideally sending the old guts in for recycling back into feedstock that others use for either manufacturing new or upgrading old units themselves. Or building in self-diagnosis over time, and auto-ordering new components for those that are detected wearing out. The Increvable washing machine comes close [2] in the repairability area, but it isn't open source to the point where you can read off specs to create completely compatible machines, and the company can still go after you for copying their product. [1] https://circuitmaker.com/blog/about-open-source-washing-machines https://circuitmaker.com/blog/about-open-source-washing-mach...
- jandrese 8y ago
  Sometimes those plastic gears are serving a purpose though. They can protect much more expensive parts by failing first when an error occurs. So the operators gripe about replacing a stupid plastic gear so they replace it with a metal one, then gripe when they have to replace the blown out gearbox.
  - yourapostasy 8y ago
    Yep, thanks for pointing that out to the general audience, should definitely be noted. Some KitchenAid mixers have a plastic gear for exactly that purpose. On the other hand, on an outboard motor I use, the plastic gear that wears through for a tilt lock mechanism is attached to a ludicrously expensive metal assembly that has to be completely replaced. I'm okay with the plastic gear designed as a sacrificial component. I don't like having to toss an entire assembly into the landfill, though. I'd like to be able to print/purchase just the sacrificial component and screw/glue it onto the existing still-working assembly. Event better, I'd like to send the broken sacrificial component back through to a process that breaks it back down into feedstock for recycled resins that go to manufacture products that can take slightly weaker plastic (each pass through recycling, plastic becomes slightly weaker, with virgin plastic starting at the strongest). Ideally, I'd like to see aluminum parts that are designed to crumple under the specified sacrifice load like the equivalent plastic parts, and be able to just endlessly recycle the aluminum. But I've never seen such a design of a sacrificial gear/cam/bolt, so I don't know if that is simply an impossible mechanical engineering ask by a dumb layperson.

NegativeK 8y ago

This is largely the difference between hardware projects (not just electronics -- metal and wood as well) and software. Decent quality physical things and materials can't be downloaded and reused indefinitely.

yourapostasy 8y ago

> ...and material cost (stock and bits) can get very expensive. I've been looking at CNC for a long time, and I've read that if you're starting from scratch, to allocate about the same amount that you spend on the mill itself to the consumables/logistical tail (end mills, cutting fluid, ancillary metalworking tools). Due to the steady degradation of quality design and manufacturing, and rapid support obsolescence, there is an endless supply of improvements I could make around the house if I had enough time and equipment. It bothers me greatly to hear from appliance repair techs that I must throw out an entire major appliance instead of repairing just the pieces that broke [1], because the parts are either grossly expensive, or even simply not available. I'd love to own "versioned, open source" appliances, where open specifications let everyone repair only what breaks. And when something breaks, the community can figure out the root cause and redesign for greater robustness. Like if a plastic part wears down causing a cam to miss a gear, then redesign to machine the cam out of high strength steel. Or if lots of people note a design oversight that makes a particular maintenance procedure a pain, a different access panel is designed and distributed for machining. Or if someone wants upgrade to a later version of an appliance, they swap out only the guts that change, and not the entire assembly, ideally sending the old guts in for recycling back into feedstock that others use for either manufacturing new or upgrading old units themselves. Or building in self-diagnosis over time, and auto-ordering new components for those that are detected wearing out. The Increvable washing machine comes close [2] in the repairability area, but it isn't open source to the point where you can read off specs to create completely compatible machines, and the company can still go after you for copying their product. [1] https://circuitmaker.com/blog/about-open-source-washing-machines https://circuitmaker.com/blog/about-open-source-washing-mach...

jandrese 8y ago
Sometimes those plastic gears are serving a purpose though. They can protect much more expensive parts by failing first when an error occurs. So the operators gripe about replacing a stupid plastic gear so they replace it with a metal one, then gripe when they have to replace the blown out gearbox.
- yourapostasy 8y ago
  Yep, thanks for pointing that out to the general audience, should definitely be noted. Some KitchenAid mixers have a plastic gear for exactly that purpose. On the other hand, on an outboard motor I use, the plastic gear that wears through for a tilt lock mechanism is attached to a ludicrously expensive metal assembly that has to be completely replaced. I'm okay with the plastic gear designed as a sacrificial component. I don't like having to toss an entire assembly into the landfill, though. I'd like to be able to print/purchase just the sacrificial component and screw/glue it onto the existing still-working assembly. Event better, I'd like to send the broken sacrificial component back through to a process that breaks it back down into feedstock for recycled resins that go to manufacture products that can take slightly weaker plastic (each pass through recycling, plastic becomes slightly weaker, with virgin plastic starting at the strongest). Ideally, I'd like to see aluminum parts that are designed to crumple under the specified sacrifice load like the equivalent plastic parts, and be able to just endlessly recycle the aluminum. But I've never seen such a design of a sacrificial gear/cam/bolt, so I don't know if that is simply an impossible mechanical engineering ask by a dumb layperson.