I need some help whether this is possible or not

[LawHit]

Hello everyone,

I am Daniel and im 17y/o and i really want to own a CNC machine to mostly learn and build some motorcycle parts.
Im planning on building a cnc mill mostly for aluminium and very ocasionally 5mm mild steel plates for example for sprockets or brake discs.
I am on a limited budget sadly enough so i need some insights if my idea is possible.


it will be a chinesium grade machine but i dont need more accuracy over 1mm or so 0.1 would be my target but i can get by if not. I would probably want to machine some press fit bearing housings but i will use a boring bar for that i think. I already ordered the steel for the construction and made a cad design for what i had in mind. Build platform will be 600x600x400 in milimeters, the steel i am going to be using is mostly 3mm thick 50x150mm(gantry support) and 50x50(rest of the machine) and i am going to run some 12x28x8 deepgroove ballbearings on the 50x50 steel. I am 99% sure that that is strong enough and that it will be fine however for the gantry i want to use some sbr16 rails, a pair of 750mm each with 3 bearingblocks each for the 400mm travel it needs to provide so i plan on spacing the bearing blocks appart like this: 1 block - 10cm - 1 block - 10cm - 1 block.

Again primary goal is for me to be able to complete this all fairly cheap and speed and accuracy are not given ****s about really
I dont care if it needs 12 hours to mill some aliminium then so be it. I am going to be using a er20 collet
and a 1.5kw bldc motor spindle made by the university of amsterdam as a project which i managed to buy it fairly cheap. Works really well and is very torqy
Will this all be enough to mill some aluminium?


Cheers, Daniel

[pippin88]

SBR rails would be a bad choice.

Save up for HIWIN 15mm rails from BST Automation on aliexpress (reliable seller).
They are soooooooooooo much better.

[NIC 77]

I already ordered the steel for the construction and made a cad design for what i had in mind. Build platform will be 600x600x400 in milimeters, the steel i am going to be using is mostly 3mm thick 50x150mm(gantry support) and 50x50(rest of the machine)

The best place to start is to post some pics of your cad design so we can really see what's going on.

Whether you can cut aluminum depends on the stiffness of the machine and the HP of the spindle at the RPM you use it at. Just about all CNC routers can cut aluminum with a very sharp carbide bit and very shallow depths of cut, it just takes forever on some DIY machines. Other DIY machines are freaking awesome at cutting aluminum, but those are rare. The better commercial routers that have better stiffness and a better spindle can cut aluminum really well and fast.

Where you'll end up on that spectrum is anyone's guess. Yes, you should be able to cut aluminum, but how deep you can make your cuts, and how long it will take, are the factors here. Perhaps you will only have a depth of cut of 0.01" each pass to get good results. Perhaps you will do 10x that.

What's this BLDC spindle? Want to post some pics?

I don't think the 50mm is a good width, but I haven't seen your design. Are you going to be doing some welding? That size and thickness of tubing can distort fairly easily.

For better feedback post pics. Good luck.

[NIC 77]

How big are these parts you want to make?

I was just thinking, that a better option for you may be to find yourself a used mill and do a CNC conversion. Once you price all of the components like linear rails, you may be far better off will a used mill, plus you don't have the frustration of building it and making all the surfaces flat, etc.

The problem with a mill is it doesn't have the same amounts of travel as a router, but for the parts you mentioned, those don't sound too large. You might want to take a look around and see what you can find. Even if you just used the X, Y from a medium sized mill, and added your BLDC spindle to it. I don't know. Something to think about if you just want to build this quickly and make some parts.

Also, if you end up looking at this, then, make sure to check the backlash, or have a plan to replace with ballscrews or add anti backlash nuts or something.

Good luck with whatever you do. Also, you mentioned you are on a limited budget. The costs you don't think about can creep up on you. Perhaps try to do as much of a cost estimate as you can before you buy too much.

[bostosh]

Learn the CAD, Anycad
Create your parts
Then learn machining and tooling
follow with learning CNC programming Anycam
Then buy a the machine, after this.

The programming and parts creating is far more important than a machine
Think of these machines as just a method to playback your data
I just rent someone else's and pay them to own and maintain it.

Another factor is what knowledge are you bringing into this endeavor?