Jonny's CNC portal mill
Posted: August 9th, 2016, 4:43 am
Hi all,
As you may know I've been working on designing a 3D printer for some time now. I got to the point where I could really use a CNC mill - so here I go and make my own CNC portal mill!
I didn't buy a ready-made one, because I didn't find anything that lives up to my expectations and is within my budget at the same time.
Core specifications:
Total overall size: WxDxH 1400x1050x1700 mm
Weight (currently): 280 kg
Build platform height from floor: 1075 mm
XYZ travel: 750x570x160 mm (Z depends on tool length)
Milling spindle: Mechatron HFS-8022, 2.2 kW, 24k rpm, ER20 collet, watercooled
Linear systems: Misumi SX2R33 linear rails (23 mm rail width) with two rails per axis and four carriages per axis. X carriage length 250 mm, Y 214 mm, Z 168 mm.
Drive systems: Misumi BSST1505 ballscrews (c7, 15mm diameter, 5mm pitch). X axis with two ballscrews.
The main frame is built from Misumi 40x80 mm aluminum extrusions. The build platform is made from 30x90 mm extrusions. That leaves a void on the underside of the build platform (80 mm high frame vs 30 mm high platform). This void is filled with 50 kg of concrete to give the static part of the machine as much weight as possible.
The machine's four feet also have cast concrete "shoes" which weigh 10 kg each. These shoes sit on a 15mm thick rubber mat (used for dampening vibrations of washing machines), and all of that is placed on a custom made table (26 mm solid beech wood with 80x80 mm spruce wood legs and 40x80 mm cross beams).
Mounting brackets and constructive parts are mostly made from 2.5 mm thick lasercut stainless steel parts, and some aluminum spacer parts.
Mounted on the table is an enclosure with removable acrylic panels to keep noise and dust inside.
Some more core design decisions:
I've opted to work with Misumi aluminum extrusions. These stand out from any other alu extrusions because they are VERY strong. The portal is an "all-around" construction of 30x120 mm alu extrusions which are definitely more rigid than any milled aluminum beam constructions.
The portal is screwed together using 4 M8 screws on every joint, then reinforced with 2.5mm stainless steel brackets which should give me a rock solid portal that is still lighter than a steel construction.
I haven't built it up yet so I can't tell from my own experience. But you can bet that I will put it to the test
/edit:
Almost forgot the most important part:
I will publish all the source files once I get it to work. No sense in publishing it earlier because there surely is some fatal error somewhere right now. If you want to take a closer look, I can send you the step (or SpaceClaim) file by mail. Just send me a PM and please respect confidentiality with the files.
Will keep you guys updated on the build. For now I have ordered screws and nuts worth 650 CHF (omg) and the alu extrusions and X axis rails (1100 EUR). The rest of the linear hardware (2200 EUR) and the CNC parts (don't even want to calculate that) will have to wait because my budget is really blown right now. Will be living on bread and water for the next few months..
As you may know I've been working on designing a 3D printer for some time now. I got to the point where I could really use a CNC mill - so here I go and make my own CNC portal mill!
I didn't buy a ready-made one, because I didn't find anything that lives up to my expectations and is within my budget at the same time.
Core specifications:
Total overall size: WxDxH 1400x1050x1700 mm
Weight (currently): 280 kg
Build platform height from floor: 1075 mm
XYZ travel: 750x570x160 mm (Z depends on tool length)
Milling spindle: Mechatron HFS-8022, 2.2 kW, 24k rpm, ER20 collet, watercooled
Linear systems: Misumi SX2R33 linear rails (23 mm rail width) with two rails per axis and four carriages per axis. X carriage length 250 mm, Y 214 mm, Z 168 mm.
Drive systems: Misumi BSST1505 ballscrews (c7, 15mm diameter, 5mm pitch). X axis with two ballscrews.
The main frame is built from Misumi 40x80 mm aluminum extrusions. The build platform is made from 30x90 mm extrusions. That leaves a void on the underside of the build platform (80 mm high frame vs 30 mm high platform). This void is filled with 50 kg of concrete to give the static part of the machine as much weight as possible.
The machine's four feet also have cast concrete "shoes" which weigh 10 kg each. These shoes sit on a 15mm thick rubber mat (used for dampening vibrations of washing machines), and all of that is placed on a custom made table (26 mm solid beech wood with 80x80 mm spruce wood legs and 40x80 mm cross beams).
Mounting brackets and constructive parts are mostly made from 2.5 mm thick lasercut stainless steel parts, and some aluminum spacer parts.
Mounted on the table is an enclosure with removable acrylic panels to keep noise and dust inside.
Some more core design decisions:
I've opted to work with Misumi aluminum extrusions. These stand out from any other alu extrusions because they are VERY strong. The portal is an "all-around" construction of 30x120 mm alu extrusions which are definitely more rigid than any milled aluminum beam constructions.
The portal is screwed together using 4 M8 screws on every joint, then reinforced with 2.5mm stainless steel brackets which should give me a rock solid portal that is still lighter than a steel construction.
I haven't built it up yet so I can't tell from my own experience. But you can bet that I will put it to the test
/edit:
Almost forgot the most important part:
I will publish all the source files once I get it to work. No sense in publishing it earlier because there surely is some fatal error somewhere right now. If you want to take a closer look, I can send you the step (or SpaceClaim) file by mail. Just send me a PM and please respect confidentiality with the files.
Will keep you guys updated on the build. For now I have ordered screws and nuts worth 650 CHF (omg) and the alu extrusions and X axis rails (1100 EUR). The rest of the linear hardware (2200 EUR) and the CNC parts (don't even want to calculate that) will have to wait because my budget is really blown right now. Will be living on bread and water for the next few months..