Jeff Epler's blog

Zenbot is back in business

Small circuitboard injects home switch signal into encoder cable

After weeks of not touching zenbot, I finally milled some circuit boards. Of course, they were for the zenbot itself.

Zenbot upgrades

After some tiny little problems with ruined stepper drivers that I don't care to talk about, I kept moping on IRC until Sam found me these pittman dc servos and I ordered some, intending on upgrading the zenbot to servos.

New screws and nuts for the zenbot

At Chris's suggestion, I bought new acme leadscrews and dumpstercnc anti-backlash leadnuts. This was to replace the old triangular leadscrews and brass nuts, which measured huge backlash, .010" or more on X. This was due at least in part to wear on the nuts: fine brass dust was visible around the leadnuts after I ran a stall test of 1000 inches or so at 1.5ips; I had earlier measured the backlash as only about .005".

Zenbot: more success milling circuit boards

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Scan of milled circuit board (full version is 600DPI

Another day, another circuit board. I'm getting to the point of thinking that with all my enhancements to the Zenbot it is becoming pretty reliable at making milled circuit boards.

Zenbot with Wolfgang Engineering "TB" Spindle

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Milling comparison. Left, Dremel 300; Right, TB Spindle.

I bought the Wolfgang Engineering Triple Bearing spindle off ebay. The seller, Richard Stethem, apparently custom builds each one. The customized spindle mount was exactly to my specifications and mounted on the Zenbot without fuss. Having milled one tiny board on it, I have to say that the difference between this and the Dremel 300 is night and day, with the TB Spindle playing the part of Day.

Zenbot gets home switches

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Y-axis home switch

Last week I added X and Y home switches to the zenbot. Here are some photos. I need to better organize all those wires!

Zenbot Tool Length Sensor

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Probing for tool length

Chris was kind enough to help me make an angle bracket to mount a tool length sensor.

Zenbot Lives

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New metal table

Nearly a year ago, I got an inexpensive CNC router off ebay. It is constructed from HDPE, and the original table was made from wood. Unfortunately, I found that the table was not flat enough for milling circuit boards. With a few upgrades, though, I've made a usable circuit board and have good hopes for the machine's usefulness in the future.