CoreXY Portal Mill/Laser

After buidling my first eShapeOKO CNC in 2012 i really liked the Makerslide approach of linear rails - just simple and cheap. Since that i always tried to build something similar, but even cheaper. I tried different stuff on my laser-engravers v1-v4 the last years.

This time the idea was to build a coreXY principle portal using off-the-shelf components. As the used Bosch type 20×20 and 20×40 profiles and the GT2 belt are that cheap, id decided to go a bit bigger with 1500x1000mm rails. This gives me the opportunity - assuming the portal and my Z-Axis do the job - to cut 3/6mm DEPRON foam boards (1250×700) for my RC-Planes, maybe even soft plywood or balsa. If not, the portal will be used for something else. There is although another Laser Module lying around here…

After sourcing all needed parts and taking bolts, washers and cables from my stock i ended up at ~140€ for the whole build (without Z-Axis).

Here we go!

buildlog:

Building the portal out of 2020 and 2040 aluminum profile and matching brackets was straight forward. I was impressed of how good the small mini wheels were running on the normal cheap - non v-slot - profile. The mounts for the motors and pulleys as well as the wagons were milled out of 6mm HPL (high preasure laminate) material on my eShapeoko. Everything was screwed together with T-Slot nuts. I was aware that coreXY needed longer belts, but a bit surprised that this machine needed full 10m of Belt for a portal with 1500x1000mm size.

On the electronics side, the Cheap Arduino Uno with grbl shield does a great Job. GRBL 1.1 was compiled with coreXY support enabled and the homing procedure modified to home the long axis (X) first and the portal (Y) after that. First run tests with the latest UniversalGcodeSender Platform showed a max speed of ~20000mm/min. Nice ;_)

Plans: CoreXY plans as DXF drawn with librecad.

• 20x40 Profile I-Type 2x1.45m 2x 10€
• 20x40 Profile I-Type 1x0.945m 7€
• 20x20 Profile I-Type 2x1m 2x 3.20€
• 28x28 Profile Brackets $3
• M5 T-Slot Nuts $5.50
• Openbuilds style Small wheel with Bearing 2x10pcs 2x $8
• M5 Excentric Spacers 10pcs $3.50
• Bunch of M5x10 M5x40 Screws, M5 Spacers and M5 Washers.
• 6mm HPL (High Pressure Laminate) for all CNC Parts.

• 10m GT2 Belt $10
• 16T GT2 Pulleys 5mm for NEMA17, 6mm for Pollin NEMA23 $4
• 5x T20 5mm Bore Toothed AND 5x T20 5mm Bore Toothless $10

Mechanics Total: ~85€

• Arduino Uno + GRBL Shield + DRV8825 Drivers $14
• Limit Switches $2.6
• 48mm NEMA 17 Motors 2x $12 planed: Nema 23 Pollin Motors have 6mm Axis!! 2x 10€
• Plastic Enclosure 135x95x45 3€
• Cable 8x0,56 + 3x2x0.9, 5 m 8€

Electronics Total: ~50€

• Modding the CNC/GRBL Shield for grbl Versions >=0.9 (exchange Z-limit and spindle enable pin): https://github.com/grbl/grbl/wiki/Connecting-Grbl
• Compiling GRBL with coreXY Settings https://github.com/grbl/grbl/blob/master/grbl/config.h#L145

Small Z-Axis with RC Heli Motor as Spindle.

• 4000kv Heli Motor $14 4000kv Car Motor $14
• XM30 A ESC $13 flashed with BLHeli, PWM input enabled, damped light disabled.
• Coupler 3.17-3.17mm $2
• 1.5mm Endmills with 3.17mm shaft $1
• FR2-5ZZ Bearing $3
• 25mm M3 Standoffs
• MGN9 Linear Rail $10
• ACT 16hsl3404 Linear Stepper Motor 15€

…coming

3.5W Laser Modul …was very cheap while the banggood anniversary.

testing the wagons

testing the portal

testing the Z-Axis

First Test of the machine with Z-Axis and Spindle installed.

Cutting the Vacuum Table out of Styrodur. Feed 10000mm/min Depth 15mm

Cutting some 4mm Plywood. Feed 1000mm/min depth 4mm. Vacuumtable holds the plywood.

GRBL 1.1 Settings:

Grbl 1.1f ['$' for help]
>>> $$
>>> $G
>S100:ok
>S0:ok
$0=10
$1=25
$2=25
$3=1
$4=0
$5=0
$6=0
$10=17
$11=0.010
$12=0.002
$13=0
$20=1
$21=1
$22=1
$23=3
$24=1000.000
$25=10000.000
$26=250
$27=2.000
$30=1000
$31=0
$32=0
$100=40.000
$101=40.000
$102=200.000
$110=15000.000
$111=15000.000
$112=1000.000
$120=400.000
$121=400.000
$122=10.000
$130=1310.000
$131=760.000
$132=400.000