new and hopeful

[Jed Clampit]

Hi all
thought i would give a quick intro
for the last few weeks i have looked round various sites with a view to acquiring a cnc machine. i have no knowledge other than what i have gained over the last couple of weeks therefore i have much to learn. i started off by looking at evil bay and the imported versions and while looking into their reliability i was lead to this fine forum
the cnc machine will be used to make relevantly small plastic parts but i have read some comments to say its not good to cnc plastic ? i was thinking of a machine with a cutting area of about A3 size with a cutting depth of 2 1/2 to 3 inch if possible. i have no knowledge of the electrical side of things but have manufactured various things over the years in wood, metal and acrylic so building the main frame shouldn't be to much of an issue. couple this to some of the comments i have read about being able to build your own 'superior' machine for the same money as the imported ones is the reason i have decided to take this route. so i will carry on reading the forum for now but be prepared for lots of 'how do i' questions

[blackburn mark]

i have read some comments to say its not good to cnc plastic ?

i cut plasics almost exclusively acetal/delrin iv done a bit of ABS
i have no idea why anybody would think cnc'ing plastic would be a problem

so i will carry on reading the forum for now

theres plenty to go at :)

[wilfy]

hopefully you will ask alot of the questions that i need to ask aswell hey :D, if you want any information about ballscrews i suggest you look at this thread http://www.mycncuk.com/forums/showth...ned-ballscrews as i've just asked a few questions about them myself, i havn't got much further than this yet.

oh & welcome to the forum, its fun here

[Jed Clampit]

i have no idea why anybody would think cnc'ing plastic would be a problem

something to do with the speed of the cutter melting the edge ? don't quote me as i could well have misunderstood the posting

thank you for the link Wilfy. belts it is then, i have learnt something else already LOL

[blackburn mark]

something to do with the speed of the cutter melting the edge ? don't quote me as i could well have misunderstood the posting

ahhh.... i heard ABS can be a pain in that regard, iv had no problems so far though with ABS its not as nice as acetal to machine but if your careful and use single flute carbides (sharp) you should be fine

[JAZZCNC]

so i will carry on reading the forum for now but be prepared for lots of 'how do i' questions

Yes please ask every question that comes into mind no matter how dumb you think it sounds.!!

Best advice is don't go rushing buying parts etc untill you have fully come to a design that suits your needs. If possible design it in Cad to ease the build and reduce errors from component clash's.!!. . . Call the first drawing V1 and when your at around re-vision V1.8 you'll just about be ready to think about whats needed component wise.!

Good luck and it's easy if your methodical doing it in the right order and treat it like eating an elephant.? . . Small pieces at a time.!!

[blackburn mark]

treat it like eating an elephant.? . . Small pieces at a time.!!

or your brain will melt!

haha! :) i like that one jazz

[JAZZCNC]

or your brain will melt!

I Like that one as well mark.!!. . . He's not joking I spend so many hours on the phone to folks who's brains turned to mush from information overload that I'm considering starting my own CNC shrink clinic. .

[Jed Clampit]

If possible design it in Cad

Ahh there lies another problem i have to over come. i once tried using cad and not having the faintest idea what i was doing, gave up very quickly
thank for the welcomes BTW

[JAZZCNC]

Ahh there lies another problem i have to over come. i once tried using cad and not having the faintest idea what i was doing, gave up very quickly
thank for the welcomes BTW

Like Bruce (motoxy) says paper and pen will get you the machine done just not has efficient or convienant when it comes to the counless design changes you will want or have to make.! . . . . BUT I suggest you start learning ASAP because without Cad skills the machine will be of little use.!

The software is a very often under estimated aspect when building a machine and in reality it's one of the hardest and most time consuming aspects to CNC.
To succesfully use a CNC machine then you will have to learn and master what is affectively 3 pieces of software.!! . . . I say effectively because 2 can be combined into one piece of software but they are still affectively 2 separate process's.?

2D CAD or vector line graphics creation is the first in the process of creating 2D toolpaths or G-code files containing all the toolpaths required to cut the complete part.
The process for 3D part machining is similiar but requires 3D solid models from which the surfaces are used to define 3D/2.5D toolpaths from.

CAM comes second and it's here were the toolpaths for each process or operation of the finshed part are defined. Toolpaths are paths and instructions that the tool for that particular operation of the part IE drilling etc will follow.? . . Here things like tool size and depth of cut, feed rate, spindle RPM etc are set.
When all toolpaths have been defined and setup, of which there will typicly be several per part, they are ouput to a single G-code file or they can be output individually has G-code files.

Lastly comes the control software which runs and controls the machine by following the instructions in the G-code file and monitoring various input signals. It also handles other areas using output signals to control things like spindles, vacuum, coolant etc.

The CAD and CAM can be combined in 1 piece of software or done individualy in different packages. Often the separate softwares are more powerful or versatile.

So get learning CAD and if possible Cam ASAP has it will be a massive help when the machines built and you'll hit the ground running so to speak.!!

Hope this helps more than confuse's.!!!!!