June 20, 2019 | ProgressTH Version 3 of our 3D printed DIYbio microcentrifuge is now on Thingiverse. There were a lot of problems with our V 2.0 but it worked. When the hinges began cracking we saw an opportunity to redesign it.
The new additions include:
- New press-fit rotor that is lighter, uses less material and allows it to be placed beneath the platform;
- a containment section that better isolates the rotor from the electronics;
- a recessed plunger for the safety microswitch to prevent the switch from being activated while the lid is open;
- removable motor mount to accommodate all varieties of motors;
- stronger hinges and a locking system to keep the bolts in place better and;
- an offset bolt-latch system making it easier to insert/retract the bolt.
It is still run off 12V DC with a DC motor, rocker switch, and microswitch keeping the electronics very simple.
It uses 3 M3 x 30mm bolts and nuts for the hinges and latch, and 2 more M3 bolts (any length, but the shorter the better) for securing the platform to the case with the containment segment sandwiched in between.
The rotor needs to be remodeled for higher resolution and balance, but other than that this so far is a much more solid design, much safer, and simpler to build.
Our older centrifuges had the rotor and tubes spinning above the platform, meaning that even with a safety switch cutting power when the lid was open, it would still be spinning pretty fast and pose a danger of clipping anything or anyone who got too close.
Without getting into microcontrollers, solenoids, or servos, the recessed rotor makes it much safer and requires you to really go out of your way to make contact with the rotor while it spins down. Getting clipped by the tubes (which are hard to see when spinning and hurts!) is impossible since they are spinning beneath the platform now.