Elegoo Mars Heater - fits JP twin rail upgrade

thingiverse

**Updated with backlash bearing mod. This customisation of the "Photonsters PTC Heater Unit" by X3msnake includes modifications to make it compatible with the Mars 3D printer. The body and secure locating parts are all printable on the Mars, requiring two prints: one for the main body and another for everything else. Supported files have been included in the download. I created this modification when I upgraded my Mars to use the Jackson Products twin rail system, replacing the original Photonsters Unit that was stuck to the base using velcro. With the twin rail system, there was no longer enough space inside the case, so I designed a customisation to remove the magnet holders from the original Photonsters body and replace them with push fittings for 15mm copper tube. This modification adds a cable tidy system that channels the cable through the top of the heater unit, down the unit, through the copper, and out through the support foot. The top cap fixing also serves to hold the temperature sensor cable, which hangs down from the top cap, allowing temperature measurement near the resin reservoir. The customisation uses push fit 15mm copper plumbing tube to connect all parts. By adding a rubber sealer to the bottom of the Mars UV cover and cutting away some rubber for the cables to exit, this system is entirely non-destructive to the Mars. ### 15mm Copper Lengths These measurements allow for a couple of mm adjustment at each joint: * Top cap >>> 90° Bend 27mm (6mm visible) * 90°Bend >>> Heater body top 32mm (10mm visible) * Heater body Bottom >>> Dogleg 35mm (10mm visible, the top of the pipe requires drilling or filing to allow for the cable.) * Dogleg to foot >>> 32mm (9mm visible) I recommend avoiding standard brittle resins for the body and instead using a resin like ABS, which seems to work fine. Standard resin resulted in a cracked body when I pushed in the temperature control. This method can also be used on the standard Mars to provide secure fitting and cable routing for the Photonsters heater solution. The same electronic hardware is used, so I suggest looking at the original item for hardware instructions: https://www.thingiverse.com/thing:3442165 ### Update 06 March 2020 - Anti Backlash Bearing I added an alternative top mount to accommodate a backlash bearing remixed from https://www.thingiverse.com/thing:3918220. The design requires a 3200RS angular bearing (10x30x14.3). I recommend fitting and removing the bearing a couple of times before curing, as it's a tight fit. The top plate fixing is by design relatively loose, so it stops any unwanted stress in other directions. When printing on the Mars, use Elegoo ABS as a minimum strength resin. You'll probably break at least one end cap screw finding out how tight you can go, so print 3 or 4 of them. Installation is pretty straightforward: 1. Remove the top cap from the Mars. 2. Screw the seat screw onto the Z-axis thread until there's 20mm or so of the thread showing. 3. Drop the bearing in and tighten the cap screw down. 4. Slide the top mount over the bearing, then slide the top cap into the mount and screw it on. 5. Finally, tighten the Seat screw. I found that I could set the g-Code z-axis to 155, which left around 1mm of free space. Since my original g-code was set at 150mm, no print height is lost over the standard, leaving a maximum print height of 150mm assuming a 5mm lift height.