Big 3D Printer #BFP

200 x 200mm cubed print area just wasn’t going to cut the mustard anymore. Using a big 3D printer with a 300 x 300mm print area changed me forever. After two years of designing and building I present to you my printer the BFP: Big FPrinter!

The Design

I went through several iterations of my design in CAD before making anything physical. I had some 8mm rods and bearing blocks left over from my old delta 3D printer project so I tried to factor them into this build so I’d have less new stuff to buy. Unlike my delta 3D printer I knew this time I wanted to stick with a cartesian configuration and ideally an h-bot or core xy setup as they remove the need to lump around the weight of a stepper motor attached to the gantry.

I also knew I wanted the printer to be enclosed so the chamber could heat up to provide a better printing environment for ABS which warps significantly if it doesn’t remain at a stable and a warm temperature while printing.

I decided on making the frame out of 2020 aluminium extrusions as they are a breeze to connect together and provide good strength.

For linear rails I went with 12mm THK style linear rails for the X and Y axes to provide silky smooth movement while also being very simple to install. The Z axis is utilising left over 8mm linear rods and bearing blocks from previous projects.

The X and Y axes are driven with GT2 belt in a core xy configuration using several GT2 idler pulleys to wrap a long GT2 belt around the gantry. Initially the Z axis was driven by a 10mm trapezoidal leadscrew however it was unfortunately sent to me slightly bent and was unusable so I upgraded to 12mm ballscrews.

A very heavy 12mm thick aluminium plate is used for the 300x300mm print bed/platform. I would’ve ideally used a 6mm or 8mm thick piece of aluminium but I was able to get this 12mm plate for free so I went for it!

You can download the design here (Need SketchUp 2020 to open)


The Parts

After the design changes began to slow it was time to start purchasing the parts which I primarily obtained from AliExpress. Here’s a list of all the parts I purchased along with the approximate amount I paid for each:

QuantityNameDescriptionApprox. Cost (USD)
15500mm length 2020 aluminium extrusionsFor the frame of the printer$61.50
3350mm MGN12 linear rails and MGN12H bearing blocksLinear rails for the X (1 rail) and Y (2 rails) axes$44.50
4500mm length 8mm linear railsLinear rails for the Z axis$22.50
88mm bearing blocks (LM8UU)Linear bearings for the Z axis$15.00
2500mm length ballscrews (SFU1204)Linear drive ballscrews for the Z axis$44.00
2Ballscrew bearing blocks (BK10)To hold the ballscrews$18.00
2NEMA 17 0.9 degree stepper motorsHigh resolution stepper motors for X and Y axes$24.00
1NEMA 17 1.8 degree stepper motorZ axis stepper motor$9.00
1BigTreeTech SKR Pro w/ 4 TMC2130’sControl board and stepper motor drivers$52.00
1300mm 240V 500W silicone heaterHeater for the heated print platform$18.50
1E3D Hemera hot end and extruderHot end and plastic filament extruder$118.00
100M5 2020 nutsThese are used to fix several of the parts to the 2020 frame$8.00
1GT2 belt 5MBelt for the X and Y axes$4.50
4GT2 20T idler pulley w/ teethTo guide the belt for the X and Y axes$8.00
6GT2 20T idler pulley w/o teeth^$16.50
2GT2 20T pulleyFor the X and Y stepper motors$4.00
3GT2 40T pulleyFor the Z stepper motor and each ballscrew$7.00
1Trianglelab 3D touch bed level sensorZero touch probe for levelling the bed$14.00

First Prototype

To get things going quick I brought some 4mm black acrylic and laser cut out all the various parts on a friends laser cutter. The frame’s bolted together with L shaped nuts and corner bracers to add stiffness. I was stunned by how quickly this thing came together, however after some test prints I discovered that the perforated bed wasn’t my favorite and the PCB heater heating it was gutless and took much too long to heat up.

Worst of all however the h-bot configuration seemed to have some tiny amount of slack which would never do, I was adamant to not have a repeat of how my last 3D printer turned out. From this I decided to redo all the parts in aluminium and change to a core xy configuration. Core XY unlike h-bot utilises two belts which wrap slightly differently around the machine allowing the belt to always be in tension.


Old Z Axis Leadscrews

The leadscrews are T10 2mm lead 2mm pitch. I used my lathe to turn down either end, the top end uses an M8 nut to clamp on a 608 bearing while the bottom end has a long section to fit a 30T GT2 pulley and a ? bearing. One leadscrew on the left side of the machine and one on the right, both driven by the same stepper motor.

As mentioned previously however these leadscrews had a slight bend in them which caused them to wobble while turning. That wobble in-turn made my 3D prints have a wobbly pattern on the vertical axis and was unacceptable. I tried to bend the leadscrews straight but it was a lost cause.


New Z Axis Ballscrews

At this point I decided the printer deserved the best so I ordered some 12mm ballscrews which are not only slightly thicker but also will provide much smoother movement and be of a higher quality.


Z Platform

The platform is pretty simple, mainly made from bits I had lying around. There are two L shaped aluminium angles bolted to four 1515 openbeam lengths. There’s four holes on each corner which attach the large 12mm thick aluminium print platform, separated by some sturdy springs. The M5 bolts then have nyloc nuts screwed on which allow the bed to be levelled by turning these nuts in either direction.


Old Extruder

I decided initially on a cheap clone extruder. However I planned to buy something better once I knew that my design for the printer didn’t contain any fatal flaws. It’s a V6 style clone which I printed this three fan mount for which you’ve got to admit does look pretty cool. The print quality was decent but it did seem to get blocked quite a lot which was annoying to say the least.


New Extruder

After the printer proved itself a decent printing machine I decided to invest in one of the best extruders out there; the E3D Hemera. To be very clean and tidy with the wiring I created a little PCB which adapts the various electrical components (hot end cartridge, thermistor, BLTouch, fans) to a 20 pin header.

I machined a little bracket on my CNC router to hold the PCB in place which needed to be a little beefy as the printers electrical umbilical cord will hang off it. I also 3D printed this cool part cooling fan mount that bolts handily on the side of the extruder. Lastly I printed a small bracket that holds a BLTouch probe on the opposite side to the part cooling fan.


New Aluminium Core XY Setup

After finding the H bot setup and the acrylic construction a little slack I decided to switch to a core xy setup and machine all the parts from 4mm aluminium. Luckily I’ve got a CNC router lying around which I was able to pull out of storage and pop out these lovely new aluminium parts.

As the belts wrap around the machine they need idler pulleys to spin around, for these pulleys I used GT2 idlers with 5mm bores. I used my lathe to turn down some 5mm steel rods for the idler bearings to run on. Here’s the pulleys mounted to the front of the frame.

Idler bearing installation on the gantry:

The new gantry had me feeling pretty chuffed. Between the core xy configuration and the new aluminium extrusion, it’s solid as hell, and looks quite pretty to boot.


Frame Assembled

I wish I had taken more photos of this part but there really wasn’t too much to it. The 2020 extrusions simply bolt together using some angle brackets and that’s that! I have 3D printed parts which hold the 8mm linear rods for the Z axis in place and bolt to the 2020 directly via M5 nuts that slide in the 2020 extrusion allowing easy adjustment and alignment.


Electronics

All the electronics are installed on a PVC sheet that is bolted to the bottom of the printer. The back left corner is home to the BigTreeTech SKR Pro controller board, two 40mm fans sit behind it that pull air over the TMC2130 stepper motor drivers to keep them cool. The back right corner is where the power supplies live; the larger power supply is 24V 10A and supplies the power for the stepper motors and hot end. The smaller 5V 5A power supply is to power the Raspberry Pi and the LED strip which lights up the inside of the printer.

Speaking of the Raspberry Pi, it lives at the front left corner of the printer and connects to the SKR controller board via USB. A long CSI cable exits the Raspberry Pi and climbs up the frame to the camera which overlooks the printing bed from the top of the frame.


Software

The brains behind the operation is the magnificent OctoPrint which installs onto a Raspberry Pi and allows you to manage your 3D printer via a incredibly customisable user interface. It’s such a cool bit of kit and has almost every feature under the sun due to it’s support for developers to make plugins that extend the features of the system. I love being able to sit on the couch and open up the webcam feed to see how the print is going.

For the software that actually pulses the stepper motors to make them turn; is a job perfect for Klipper. Klipper, unlike Merlin, does away with doing all the G-Code processing on the embedded microprocessor and any other costly operations relying instead on a more powerful processor such as a Raspberry Pi to do that number crunching. With the extra time on it’s hands it dedicates that to what a small embedded microprocessor does best, which is performing very accurate, realtime driving of the stepper motors. This allows Klipper to run stepper motors at faster than ever before speeds with exceptional accuracy.


The Finished 3D Printer

Well everyone, that’s that! After two years, multiple moments where I felt like throwing in the towel, I present to you my completed 3D printer.

As with every project there’s more things I want to do, small things to upgrade or change but as it stands this is a very capable printer. Between the great E3D hot end, the very powerful heated bed and the enclosed chamber it can print some really big ABS parts that come out looking great and are incredibly solid.


Alternatives

Several people have asked me if there’s an easier option to get started in 3D printing without building a behemoth 3D printer like I did. There certainly is some great off-the-shelf options that don’t break the bank and will get you up and running fast. I personally would recommend the Creality Ender 3 series of 3D printers. They have excellent print quality and are (in my opinion) so very cheap that they’re almost a no brainer. If I could go back in time I might’ve just bought a printer like an Ender but I was in the unique situation that I already had a lot of the tools and materials needed to make my 3D printer.


5 thoughts on “Big 3D Printer #BFP”

    1. Hi there. Yep can do, hopefully I’ll be able to tidy it up and get them uploaded here within a few weeks.

    1. Thanks! There’s a 3D printed clamp that sits above the extruder, it’s a bit awkward but to use it you pull the belt taught with one hand and with the other tighten the belt clamp.

  1. Pingback: 3D Printed Guitar That Lights Up As You Play - Joshendy Blog

Comments are closed.