small CNC Milling machine from Aliexpress - Page 1
Forum section: electronics / general

author: teus
author_rank: Contributor
timestamp: September 03, 2018, 03:37:57 pm
content: I'm looking at CNC milling machines on Aliexpress. I would like to learn milling parts, mostly aluminum, with a size somewhere up to 100x100mm.Proxxon has a small milling machine for ~400 euro, and it's available in a CNC version for ~800 euro, but that's too expensive.Does anyone have some advice or starting point for finding a machine?Some machines are labeled both as router, engraver, milling machine... They can mount lasers too. Some machines come with a parallel port to connect your PCThis one is quite popularhttps://www.aliexpress.com/store/product/CNC-2417-DIY-CNC-Engraving-Machine-3axis-Mini-Pcb-Pvc-Milling-Machine-Metal-Wood-Carving-Machine/1988027_32842617804.htmlHere I found some comments and info about it:https://www.reddit.com/r/hobbycnc/comments/5mvgnn/chinese_2417_cnc_for_doing_inlay_work_in_wood/This one seems a bit more serious (and still within budget), but I wouldn't want a parallel port interface:https://www.aliexpress.com/store/product/DIY-3-Axis-CNC-Milling-Machine-300W-Spindle-Wood-Carving-Router-Machine-Russia-free-tax/1665581_32744743657.htmlThis one seems to be beefier and with USB:https://www.aliexpress.com/store/product/Mini-CNC-2418-CNC-Engraving-Machine-3axis-PCB-Milling-Machine-Metal-Wood-Carving-Machine-CNC-Router/3085068_32861234066.html

author: Eka
author_rank: Regular Contributor
timestamp: September 05, 2018, 02:30:43 am
content: Save up...If you want any worthwhile degree of accuracy, it'll need to have some mass to the components that milling forces travel through. This is to counter cutting head chatter and deflection forces on the rods due to the cutting head pressure against the material being milled. I didn't see a single low cost one on Banggood that was sturdy enough for doing metal blocks. Wood and plastics, yes. Thin metal plates, maybe. You may be able to get away with using spiral cutting bits which chatter much less, but there will still be deflection from the cutting forces. All of the designs on Banggood effectively have just 1 rod to counter horizontal deflection of the head, and I don't think any of the rods are thick enough. I've been thinking of making an extrude, and mill plastic 3D printer that could do some metal milling, and was looking at using three 20 mm diameter rods for the head to travel along. The gantry would travel on two supported rails mounted to it's edges. I'd have a 1" thick cast plate of aluminum t-slot groved, then v-grove milled along the long sides for the rails to be attached to. I think I'd move the gantry at first with belts, but plan for gear racks in the future.Something to think about is lost plastic casting methods. The part shape can be printed by a plastic extruding 3D printer, then cast using lost wax techniques to get a metal part. It is also possible to mill wax blocks for lost was castings.

author: donotdespisethesnake
author_rank: Super Contributor
timestamp: September 05, 2018, 06:10:54 am
content: Quote from: teus on September 03, 2018, 03:37:57 pmIf you are serious about milling metals, even alu, you need to pay for a proper machine. Cheap stuff from China won't cut it. They are OK for carving wood or soft materials, engraving.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 05, 2018, 07:31:48 am
content: I have a 3040 "engraver" which I mostly use for cutting FR4, which it does pretty well.I would highly recommend using one of the standalone CNC controllers, e.g.This oneso you're not having to mess with parallel port stuff etc.If the main goal is learning then it probably makes sense to buy something cheap to start with, as it will give you experience and insight into the limitations, and you will get a better idea of what you will need later.