Build log: 3D printer Anycubic Predator Height mod

Here I describe my steps on extending the delta 3D printer ‘Predator’ by Anycubic to 950mm z height. I built this mod in April 2019 and the printer is still currently in use.

General information about this build
The build volume for the Anycubic Predator is originally 450mm z height, and 370mm diameter for the build plate.
The printer itself is well over 1 meter tall due to the fact it is a delta printer: the rods need atleast half a meter of space to be able to reach all corners in the build plate due to the type of movement of a delta printer. With the height mod, this printer is up to 160cm tall.

The reason why I choose the Anycubic Predator for my height mod: Delta 3D printers are more suitable for height mods. Their triangular structure and fixed build plate makes them more stable at larger heights, and they print a lot faster due to the combined effort of 3 stepper motors to move the extruder. The Predator is also standard equipped with a floating extruder drive, which makes the bowden tube a lot shorter and no need to extend it to immense lengths at height mods which would stress the bowden system a lot. The Predator also does not require any firmware or board changes to do the height mod.
My other option for the height mod, which has been done before, is the Tevo Little Monster. Similar specs and similar price, but much harder to obtain for me in the Netherlands. Currently, both delta printers are no longer in production. I don’t currently know a delta option with which you could do this mod. The Flsun V400 for example has a custom gantry and pillar system which would be difficult to completely swap out.

Information about the gantry carriages and the aluminium extrusions (the pillars)
The Predator uses custom 1000mm long aluminium extrusions as the core of the 3-pillar frame. These are very similar to the standard aluminium 4080 ‘C-beam’ style extrusion which have a 40mm gantry gap, but the original pillars sport a wider 42mm gap for the gantry. I didn’t know the dimensions of the Predator frame and instead winged it, which worked out for me after filing down 2mm of the gantry plates drilled holes, so the original gantry carriage would fit in the 40mm gap. It would have been much easier if i bought 3x standard open-build gantry carriages instead (but more expensive). You can take apart the carriages for the predator and install the original rod mounts on the new open-build carriages.
Maybe a tip to get those open-build gantry carriages, if you don’t want to file down aluminium by hand.

3x 1500mm Aluminium 4080 extrusions ‘C-beam’ style
3x 3000mm GT2 6mm reinforced belts
Some electrical wire and a way to connect them to lengthen the wires for the heated bed and hot-end

Centerpunch and hammer
Drill with HSV drills (M5, M6, M10-12)
Tap and die set
Metal files (if you’re not getting new gantry)
Voltmeter + soldering equipment or wire connectors etc

I had to disassemble the entire 3d printer back to the ‘starting’ point, that is, how you get the printer with the frame disassembled to the 3 pillars and the top/bottom frames.
I took off all the gantry carriages and belts, noted the dimension and placement of the drill holes in the original pillars, and marked these in the new c-beams i bought. Make sure you transfer the holes precisely, as it determines the mechanical accuracy of the whole frame.

Using my centerpunch I punched some holes at the markings.
I measured the dimensions of the original screws that go into the frame and make sure the drilled holes matched those. I had to use some M10-M12 drills to drill away the outer shell of the aluminium extrusions, so the bolts had better surface to be fastened (it’s similar to the original pillars so I just imitated that)

Then on the inside of the c-beams I had to drill some smaller holes, (use 1mm smaller drill than the screws) for the stepper motor mounts. These need to be tapped, so you create threading for the screws to be fixed to. I had to make sure the stepper motor mounts fit well on there and keep the 2mm gap difference with the new beams in mind. I also took this opportunity to fit the stepper motors with dampers, to eliminate sound on this printer. (if you install new board, such as an skr1.4t, no need. The drivers will eliminate the sound and dampers will mechanically affect the printer)

After mounting the stepper motor mounts and drilling the holes, i had to fit the gantry plates with the wheels in place. You can actually disassemble the rod mounts from the gantry plates and use standard open-build gantry plates, but I didnt buy those and decided to file down the holes that fit the wheels in place, so the v-wheels would fit into a 40mm gap instead of 42mm gap. This took a couple hours, but in the end it worked out great.

I had to file down the gantry plates for the idler mount as well. Then i could fit the gantry plates in place and span the belts between them. I used about 2750mm belts for each pillar.

I mounted the new 1500mm C-beams to the hotbed and the top of the predator, made sure everything was stable and parallel too.

Last part was to extend the wires with an extra 500mm to be able to fit the extra height. I kept some of the quick connectors and securely used heatshrink at each connection. I used a voltmeter to make sure that each wire was properly connected.
The bundle of cables was suspended using a retractable card holder reel, this would suspend the cables when it’s homed, and reel out when the extra length is necessary, without getting in the way of the printer head. Just place the cardholder inside the top chassis and suspend it from the same hole the wire bundle go through and ziptie it somewhere halfway to the wire bundle.

Then turned it on, homed it, and did a new level. The original board does not need any firmware changes to support the extra height. During leveling/homing however it does slow down when it reaches the original z-height, and it’ll take a bit longer to do those operations, but that’s only a very small inconvenience.

It can print small models in proper detail, and large models up to 950mm (in the middle). Keep in mind that a tall model will have more ‘skyscraper’ effect, meaning it will wobble due to the pressure of the nozzle or even break loose from the bed.
This may lead to excessive layer banding and waves in the print unless accommodated using a special print mode (vase mode, zero infill), low speed, z hop, extra wide support structure at the base, etc etc. You can experiment with several means like these mentioned, to fix it.

2024 current modification list:

Height modification with the 1500mm C-beams
Board: SKR 1.4 Turbo with 2209TMC drivers
Firmware (you need to change z height):!RD5zRJhZ!F2uRRc3gY21YocmqYpir_xRTUhxMF8X3Czd_KHabicY or
Screen: TFT35
Stepper dampers (need to remove these)
V400 effector, extruder, hotend (this is from a different delta printer FLSUN V400 and i just bought a complete effector extruder set and swapped out the original directly)
Whambamsystems flexible build plate system
Retractable caster wheels to roll the printer around easily. I drilled them directly to the sides of the pillars on the bottom