new and hopeful

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 :wink:
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 :nevreness:

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

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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

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so i will carry on reading the forum for now

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theres plenty to go at :)

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

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

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

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

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

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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

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Originally Posted by Jed Clampit

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

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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.!!

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

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or your brain will melt!

haha! :) i like that one jazz

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Originally Posted by blackburn mark

or your brain will melt!

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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. . :joker:

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If possible design it in Cad

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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

Once upon a time in the deep dark recesses of time there existed.................................pencil and paper. Pre-cad we all did are designs this way. Give it a go, it may still be available.
Lots of info here. It is also possible to get plans at a reasonable price and get some one to print them out for you for you to modify to suit your self.

Bruce

Of course you will eventually have to learn so that you can draw the components that you want to make.

pencil and paper i have heard of them but was unsure how to drive them :wink: i am sure i can sort something out for the build plans but like you say i will have to learn for the components.

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Originally Posted by Jed Clampit

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

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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.!!!!!

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or your brain will melt!

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yep its just happened LOL
OK can you suggest a starting point or some good TUT's or similar ?
i have a copy of Autocad (somewhere) and not sure of the version if that's any use or do you recommend a different software ?

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yep its just happened LOL

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youll get a lot of that :)

google sketchup might be worth a look(free), plenty of people seem to use it to design a first cnc


could do with someone jumping in and letting us know if it exports to CAM OK??

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Originally Posted by Jed Clampit

OK can you suggest a starting point or some good TUT's or similar ?

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Not sure what a TUT is other than what my girl friend does when I fart. .:beguiled:

Autocad will do fine for the 2D drawing side and depending on version possibly the 3D but to be honest I'm not up on Autocad so not best person to advise on this aspect of AC.
It will certainly be ok for the 2D side and let you output files in DXF or DWG format which will load into just about every Cam program on the market due to AutoCads DXF/DWG format being the industry standard.

My personal 2d/3D cad software is Rhinocerous but it's not cheap and very powerful, Viacad is a popular software and capable of 2D/3D at resonable price.

Regards CAM then it becomes a bit more complicated and choosing the best software will come down to a few factors.? Mainly what you want to do and how deep your pockets are.?
First what type of work you want to do with the machine will make a difference to which Cam will work best for you.?. . Basicly the toolpaths often called cutting strategies and can be tailored to suit certain types of work better than others.
For instance if you are mainly planning on creating carvings or signs or engraving etc then software which leans towards this type cutting works best giving features to allow the job to be done quicker or better/easier.

If simple profiling and pocketing, drilling type work, say like when cutting out 2D shapes, brackets, letters etc whether that be in metal, wood, plastic etc then usually a basic run of the mill Cam program can handle these things fine. Thou again there are packages that give more or better features that others, usually at a cost.!!

If mainly 3D type work where all 3 axis are moving at same time like when making moulds or complex surface shapes etc then Cam software with Good 3D toolpath stratigies become important and it's here where you'll need deep pockets for good software.

Now basicly there really hisn't one software that does every thing and does it better than anything else. The software that has better or more focused stratagies towards certain job types tend to cost the most money and can run into several hundred and thousands of pounds for top range software.

Then you have the combined CAD/CAM software.? These tend to be a comprimise in one or both area's.!! . . .BUT for most DIY usage they can be the best and most affordable package.
Often these CADCAM packages are limited to simple tools for drawing and basic cutting stratagies to keep the cost's down but if you can live with these short comings then they are a good entry level start.!

Now your thinking " OK but you still havent recommended anything" and thats deliberate with reason being that untill we or you know better what you want to cut then really It can't honestly be advised or recommend has one CAM package may be better than another.?

Give us more idea the use and I'll gladly recommend.

thank you for the info Jazz :cool:
i have had a search to see what courses are available locally but there only seems to be distant learning via dvd's. and £180 i think i would be better with youtube LOL
i will concentrate on 2-3 design before looking into the other types of software, little point getting a head of myself. at first i will be cutting out 2D shapes, brackets, letters etc but if it works well and i get into it more then more complicated work like faces and other carvings could follow.

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Originally Posted by Jed Clampit

thank you for the info Jazz :cool:. . . . . at first i will be cutting out 2D shapes, brackets, letters etc but if it works well and i get into it more then more complicated work like faces and other carvings could follow.

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Your welcome.!!

Ok then for simple stuff then CamBam is a good cheap start CAD/CAM software and will do most of what you want and will also do basic 3D work.

For the simple V-carving, engraving side then look towards the cheaper vectric offerings, for more complex and 3D carvings then you'll need there higher end offerings.

CamBam is a good starting point thou and at one time they did a free version but I'm not sure anymore.?

They still do a free version but avoid it as it is too old. You can play with the main one for a while for free.

Although I am very conversant with autocad style progs I have found the Punch Viacad is very simple to use and cheap. Infact at the moment its on offer in the states but you have to buy it from the uk, may be on offer here as well. There are utubes on it so check them out. Your not to far away if you wanted a day's lesson here in peebles.

There are cad cam packages for around the £100 mark such as artcam express that are very simple to use and there is a free trial available to download. Have a look at the vetrics site as all the software is available for free trial. cut 2d would be worth a look.

Do not be put off. All of this software can look daunting but once you start it really dose not have to be to hard. Google sketch up is the easiest once you get your head around 3d. Very good for designing your m/c and a few novices have written about their attempts on this forum.

http://www.mycncuk.com/forums/showth...ips-discussion

Bruce

Before paper, Engineers had fag packets

Cheers for the info Bruce it will be useful in the future. as for the lesson i might just take you up on that one day :wink:
i am busy at the moment (real life getting in the way) but i want to have a go at autocad/sketchup and at least try to get some understanding of how they work. in the mean time i will read the forum and try to absorb as much as possible, i am loving some of the build logs :chuncky: