This is the absolute cheapest way to get a metal frame for your Anet A8 (or other similar printer). Aluminium extrusions are super expensive here in Canada, so I wanted to created something. For this build you will need (prices in $CAD):
1x10' of 3/4" EMT tubing - 10$
About 60x #10x3/4 metal self-tapping screws - 5$
About a 1/3 of a spool of your prefered filament (I used PETG) - 10$
This project was based on hdaniel3's idea of PVC tubing for frame, so a couple of parts are highly inspired by his project. Pheneeny's AM8 was also a big source of inspiration, some parts are also copied from his project.
I predrilled every hole with a 1/8" drill bit.
You will have to cut the tubing in these lengths:
X: 3x 313mm
Y: 2x 364mm
Z: 2x 443mm
Z supports: 2x 200mm
For everybody in metric countries, scale the parts 105% to fit 25mm OD tubing and 107% for 25.4mm OD.
The frame was bolted on a 1/2" plywood using EMT straps.
Install the Power Supply and the Motherboard on their supports BEFORE putting them on the frame, otherwise the screws aren't accessible.
CAUTION: ZMotorMount_L & R have super tight tolerences for the Z tubing. I recommend using a file to smooth the printed holes, then insert it with a rubber mallet.
Added EMT8_s3d for those who uses Simplify3D and want to see their printer!
Everything was printed at 0.2mm with 20% hexagon infill. No supports are needed excepted for BeltTensionner_1. ZMotorMount_L & R might need supports, but if you have good cooling it will be just fine without.