3-Axis precision mini CNC machine - Page 1
Forum section: electronics / general

author: xzswq21
author_rank: Frequent Contributor
timestamp: August 19, 2021, 04:28:46 pm
content: HelloI want to cut and bore small stainless steel, Aluminum, Teflon sheets, for example 8"x8" or 4"x4" sheets, but the CNC machine should be precision (accuracy should be 0.05mm or better)Do you know such a CNC machine with a reasonable price?Thanks

author: Benta
author_rank: Super Contributor
timestamp: August 19, 2021, 04:32:03 pm
content: I know several such machines, but the main question is: how big is your wallet?

author: xzswq21
author_rank: Frequent Contributor
timestamp: August 19, 2021, 04:40:14 pm
content: Quote from: Benta on August 19, 2021, 04:32:03 pmplease write your Options, sometimes our wallets are stretched.

author: Benta
author_rank: Super Contributor
timestamp: August 19, 2021, 04:57:42 pm
content: Where are you in the world? The offerings differ from region to region, and shipping heavy machines is costly. It's best to go for local offerings.I don't need your adress or country, but region or just continent would help.

author: xzswq21
author_rank: Frequent Contributor
timestamp: August 20, 2021, 10:19:19 am
content: Quote from: Benta on August 19, 2021, 04:57:42 pmAsia but don't worry about the shipping cost. in the first step I should know several precision and small CNC machines.

author: mac.6
author_rank: Regular Contributor
timestamp: August 21, 2021, 05:27:51 pm
content: accuracy of 0.05mm doesn't mean anything if not specified over a length.Because anything like 0.05mm over 300mm is in class C0/C1 ballscrew, so at least 1k$ per axle...And to have this kind of accuracy you also need environment control room, otherwise it's just flushing money down the toilets...

author: olkipukki
author_rank: Frequent Contributor
timestamp: August 21, 2021, 05:56:35 pm
content: Quote from: Benta on August 19, 2021, 04:32:03 pm... and how big is your place

author: xzswq21
author_rank: Frequent Contributor
timestamp: August 21, 2021, 06:17:19 pm
content: Quote from: olkipukki on August 21, 2021, 05:56:35 pmIn my workshop at our home!

author: xzswq21
author_rank: Frequent Contributor
timestamp: August 21, 2021, 08:02:38 pm
content: I need a high accuracy mini CNC machines.

author: langwadt
author_rank: Super Contributor
timestamp: August 21, 2021, 08:26:15 pm
content: Quote from: xzswq21 on August 21, 2021, 08:02:38 pmand to give any sensible response you need to define high accuracy, mini, and how big your budget is

author: Benta
author_rank: Super Contributor
timestamp: August 21, 2021, 10:10:53 pm
content: Quote from: xzswq21 on August 21, 2021, 08:02:38 pmOK, just to give you an idea on offerings based on your wishes.This is a small machine that will accommodate your needs regarding workpiece size and accuracy (Stepcraft D300):https://www.stepcraft-systems.com/en/cnc-machines/d-seriesQuite honestly, it's a toy. It will work for wood and plastics, but will be at its limit with aluminium. Forget brass and stainless steel. Just look at its weight.This is somewhat better (CNC-STEP S400T):https://www.cnc-step.de/cnc-fraese-high-z-s-400t-kugelgewindetrieb-400x300mm/It will take your workpieces, it will machine aluminium and brass, and with care, also steel and certain stainless alloys.Here's a machine that will do almost everything you want (Wabeco CC-F1200):https://www.wabeco-remscheid.de/catalog/category/view/s/cc-f1200/id/341/It will machine everything, including stainless steel. but it has a big limitation: the Y-axis working range is only 150 mm (~6").Note that it's a cast iron machine (notaluminium), weighing in at around 105 kg.This feature is a Good Thing!Now you've seen the price ranges for what are not even production machines, but rather hobby or prototyping. Feel free to have a heart attack.Of course, copies/clones of these types of machines are available from China at perhaps half price.The reason I especially mention stainless is, that except for a few alloys, it's hell to work with for a milling machine. It's either "gummy" when cutting, or even worse, it work hardens to glass brittleness, thus needing a very rigid machine with high feed rates.

author: KaneTW
author_rank: Frequent Contributor
timestamp: August 21, 2021, 11:37:55 pm
content: Forget about CNC-STEP etc. They're not worth your money even as a hobbyist machine. CNC-STEP in particular vastly overpromises their specs.First of all, your tolerances in the motion system must be tight enough. This means high-accuracy ball screws etc.Secondly, open-loop steppers won't work here. You need a closed-loop system with a sufficiently exact encoder.Thirdly, your machine must be very rigid and low on vibration. Cast iron or granite/etc base is required.You mention stainless steel. Due to its propensity to work harden, you can't work slowly and you need flood coolant. This pretty much pushes you into big, enclosed machine territory.For example, for stainless, you also need to keep your workpiece within 15C of reference temperature to achieve 50um/200mm accuracy.You're looking at Haas Mini Mill (lighter use), DMG Mori M1 (heavier use), etc. at least imo. A Tormach 1100MX *might* be able to cut it, but that's closer to hobby territory.So 5 digits for sure, the question is just whether it's 50k or 20k base.

author: Benta
author_rank: Super Contributor
timestamp: August 22, 2021, 12:25:39 am
content: Let's not go over the top. The OP specified 0.05 mm tolerances, which is not that hard to achieve.But the aluminium based machines are either jokes or for plastic cutting. Cast iron is the thing.

author: langwadt
author_rank: Super Contributor
timestamp: August 22, 2021, 12:38:24 am
content: Quote from: Benta on August 22, 2021, 12:25:39 amnonsense,https://youtu.be/_fPTYjScd_w

author: AccountRemovedPerUsersRequest
author_rank: Regular Contributor
timestamp: August 22, 2021, 07:53:30 am
content: I have a CNC made of extruded aluminum rods and open-loop steppers. Here is an example of a routed PCB. Pads are 16mils and tracks are 12mils. How is this related to anything? Well, just sharing an example.A

author: thinkfat
author_rank: Unknown
timestamp: August 22, 2021, 09:30:19 am
content: Quote from: langwadt on August 22, 2021, 12:38:24 amStefan Gotteswinter is certainly a trustworthy source.

author: Benta
author_rank: Super Contributor
timestamp: August 22, 2021, 10:25:44 am
content: Quote from: langwadt on August 22, 2021, 12:38:24 amAt around 15:xx he says: "it is not made for cutting steel, but you can make it do it." and then shows machining a 316 block, with ridiculously small cuts.His selection of 316 is not random, 316 is one of the few stainless alloys that's can be machined without problems.I'm not saying you can't make a machine from aluminium, but then it should have a frame/bed of much larger dimensions than on the hobby machines, and then you might as well go to cast iron directly. They'll weigh approximately the same.And watch your tone, please.

author: xzswq21
author_rank: Frequent Contributor
timestamp: August 22, 2021, 11:11:37 am
content: Thanks for all your valuable commentsCan I make a customized CNC machine? There are a lot of used precision ball screw actuators and 5 phase stepping motor with encoder, these are stainless steel, plus I can design a controller to control the CNC machine, I think I should install the parts on a Iron frame and align the axes. I want to cut and bore small size pieces, 1"x2" teflon rod or a 4"x4" steel sheet with a 2mm (0.078") thickness,

author: Benta
author_rank: Super Contributor
timestamp: August 22, 2021, 11:45:57 am
content: Quote from: xzswq21 on August 22, 2021, 11:11:37 amSure, lots of people do this and there are plenty of web sites describing how. The most difficult part is probably the integration with your CAD software.

author: langwadt
author_rank: Super Contributor
timestamp: August 22, 2021, 12:46:46 pm
content: Quote from: Benta on August 22, 2021, 10:25:44 amyou blatantly stated aluminum machines are "a joke" or plastic only, and while there are plenty of machines that are that (build in all kinds of materiels) that's just not true

author: langwadt
author_rank: Super Contributor
timestamp: August 22, 2021, 12:48:18 pm
content: Quote from: xzswq21 on August 22, 2021, 11:11:37 amif you have to ask probably not, definitely not high precision

author: sokoloff
author_rank: Super Contributor
timestamp: August 22, 2021, 12:53:20 pm
content: If you want to build your own machine, I think the first step is to become familiar with a commercial machine (ideally a low-end and a mid-grade machine separately), spend a couple hundred hours making parts and chips, and see what they did and why.You wouldn’t start out trying to build a car or start a plumbing company today without experience of what already exists, right?Is it doable? Of course! Is it a lot of work? Also of course.

author: langwadt
author_rank: Super Contributor
timestamp: August 22, 2021, 12:55:52 pm
content: Quote from: sokoloff on August 22, 2021, 12:53:20 pmand a CNC is great help when building a CNC

author: thinkfat
author_rank: Unknown
timestamp: August 22, 2021, 12:56:16 pm
content: For something DIY that can mill steel, here's Marco Reps router:https://youtu.be/vB_FvkllLPcThis is the Finale of the series.Of course the frame is not aluminum.

author: PaulAm
author_rank: Frequent Contributor
timestamp: August 22, 2021, 06:24:28 pm
content: QuoteAt the very least, access to a machine shop with decent quality manual machines (and the knowledge and experience to use them). If you don't know what you're doing, the only recourse is to pay somebody for their expertise and buy a machine or kit that meets your requirements.One alternative is to get a cast iron bench mill drill (Chinese clones are all over the market) and then a refit CNC kit.. These things are > 1-300Kg, so not really that big as far as machines go. Find the refit kit first before you get the mill though.The only constant here is that it's going to cost a fair amount of money. Precision and machining steel/stainless does not come cheap.

author: xzswq21
author_rank: Frequent Contributor
timestamp: August 22, 2021, 07:31:38 pm
content: Quote from: PaulAm on August 22, 2021, 06:24:28 pmWhat do you think about this machine?https://forsuncnc.com/mini-cnc-router-fs4040a/They claimed "Cast steel table structure and side support, Aluminum gantry, aluminum T-Plate Extrusion Combined table" and "All the spare parts are a world-famous brand like Siemens controller from Germany, Yaskawa servo motors from Japan, Igus cable from Germany, ABB from Switzerland, and so on"..But it's a Chinese company and I'm scared to rely on their specifications.

author: PaulAm
author_rank: Frequent Contributor
timestamp: August 22, 2021, 08:13:03 pm
content: Looks fine for wood or plastic.

author: Benta
author_rank: Super Contributor
timestamp: August 22, 2021, 08:29:35 pm
content: Quote from: PaulAm on August 22, 2021, 08:13:03 pmYep. Quote from the description:"Mainly used in the engraving, punching, and cutting of PVC, acrylic, two-color board, engineering plastics, etc."Says it all.

author: Benta
author_rank: Super Contributor
timestamp: August 22, 2021, 09:09:30 pm
content: We should be a bit careful with metal-working machine terminology here:A fixed flat-bed machine with moving gantry is arouter.A fixed-head machine with moving X-Y table is amill.Routers are mainly for engraving and contour cutting in soft materials. The whole construction principle does not allow for the rigidity needed for working in steel (unless you make it extremely massive).A mill is a different story, and can basically be built to very high rigidity with little effort.A very popular CNC mill setup in the hobby/prototyping scene is the Sieg SX2 with added CNC kit. The machine is from Shanghai, but good quality.http://www.siegind.com/product_detail/sx2-mini-mill-drill-15008858857815262.htmlThe X2 is rigid enough for steel and SS using reasonably sized cutters (from experience: up to ø4 mm, with care ø6 mm).Ready to bolt on CNC kits are available from several supplies, eg, Heavy Metal CNC or CNC Conversion Plus.Downside to the Sieg SX2: the X/Y working envelope is just 100 mm x 220 mm.But this is about as cost-effective as you will get.

author: xzswq21
author_rank: Frequent Contributor
timestamp: August 22, 2021, 09:38:22 pm
content: Quote from: Benta on August 22, 2021, 09:09:30 pmThanksDo you know a precision lathe machine? I want to buy a Proxxon PD 250/E, it's 1600$ with the accessories.

author: Benta
author_rank: Super Contributor
timestamp: August 22, 2021, 10:27:04 pm
content: Quote from: xzswq21 on August 22, 2021, 09:38:22 pmDon't, you'll regret it. I know the PD250 well, and it's flimsy, has no features and is overpriced.The minimum I'd go for is something like this:https://www.stuermer-machines.com/brands/optimum/category/product/optimum-lathes-conventional/optiturn-tu-2004v-3420310/But I'd recommend going up one size:https://www.stuermer-machines.com/brands/optimum/category/product/optimum-lathes-conventional/optiturn-tu-2304-3420320/MT3 headstock, MT2 tailstock, proper carriage movement etc.Accessories? Pfft! The only thing you need to start with is cutters. Order those when you have a machine to be certain of the correct shaft size. They're not expensive, you can get a set of 5 different modular carbide cutters for 100 Euro (but you'll probably only need two of them).After that you can start considering drill chuck and live center for the tailstock and center drills. Also not really expensive.The links are not because I endorse the machines or have any affiliation, but to show the kind of machine I recommend. You can probably find almost identical machines at 2/3 the price as China non-brands.