Why CNC?

[tribbles]

For me, the attraction is four-fold.

Firstly, I design on a computer, so being able to just tell the computer "Take this, and make it" is fantastic - I don't need to print anything out.

Secondly, I can get a significant amount of accuracy that I wouldn't have been able to get manually. I'm designing a car body, and it's expected that a manual process would be, at best, 3mm from side to side. The computer's accuracy is significantly higher than this (I'm aiming for 1mm, but I know that it should be able to get much higher).

Thirdly, it's repeatability - if I need to make 1 'doodah', then manually it would be doable. If I needed to make 10, then it would be a bit laborious - 100, and I'd get really tired of it.

Finally, it's automatic - I don't need to watch it do its thing over many hours, so I can get on with other things while it's doing its thing.

[ptjw7uk]

The software side of things is a big problem in that you will unless you start to sell items never make up the large cost of the software.
So what are the options, cambam do a free version which I have used and is reasonable for whta I want to do at the moment. Then there is Flashcut CNC3 which loads and can create gcode for free see http://www.mycncuk.com/forums/showth...light=software post 5 by JohnS
This will get you most of the way down the learning curve.
I have Autocad Lt but it will not run on my Vista machine so I have to transfer dxf files to the vista machine so much for progress. Looking at the new Windows7 professional which will run a version of XP but needs a clean install so I'll just wait as this is a hobby and not a bottom less money pit.
Just had a dya of more learning the ins and outs of cnc in that the software used with my controller Easycnc2 has an engraving function taht I have been playing with. For small print it appears to be OK but as I wanted bigger the curves to letters was a bit lacking so, I tried the Cambam text and it was a lot rounder flowing output, So produced the gcode and input it into easycnc2 and run it in emulate wtf it was producing great swirles all over the place?
Had a look on the web for an emulator, found one download and run it text was great. Loaded the code into the mill and produced great swirles as per the emulator. Quick email to CDE produced the fact that there was an option for G02 and G03 code in that for arcs there is an option to do them in absolute or incremental fashion. Put a tick in the box and the text is now OK.

You just have to take it one step at a time!

Peter

[saxonhawthorn]

Thank you Tribbles. That's a very comprehensive and persuasive set of arguments! :)

[Tom]

can somebody explain to me why?

For me it's the same, the pleasure and freedom of being able to design something that doesn't necessarily have many straight lines in it. It's a bonus that you can make 2 or 3 in a similar time as it takes to make one (make one, sell one, give one away). My machine has only been running a couple of weeks, and isn't truly finished, but I'm loving CNC so far - if you can imagine it, you can make it!

So perhaps you can answer another question which follows on from that, namely "Which CAD?" AutoCAD is a good commercial product but hopelessly over-priced for hobby use. Whis is the most popular CAD/CAM amongst the users of this forum? Is there such a thing as a concensus?

My workflow at the moment is ProgeCAD Smart -> Cambam plus (still in my 40 trial startups) -> EMC2. This is fine for 2D and 2.5D cutting. The programs import and export via DXF.
ProgeCAD Smart is basically the same as autocad, and free for non-commercial use. http://www.progesoft.com/en/smart-2009

Later I'm going to get more into 3D forms (I have a very specific project to make a wedding present for some good friends), and have started to learn Blender (a pretty steep curve). Again export via DXF, but I haven't tested Cambam like this yet...

I don't know about a consensus though! :)

In summary, if you need to find some critical views on CNC, you probably need to try a different forum!!

[saxonhawthorn]

[quote=Tom;9740]
if you can imagine it, you can make it!

Tom, that has to be the quote of the week. :)

It was seeing all the hardware bits on eBay that set me wondering what the attraction was? But as you and others have pointed out, it's clearly the ease of CAD design that most attracts people to CNC, and I can understand that.

I think tomorrow (and probably quite a lot of tomorrows) will now be spent reviewing CAD packages. Then once I have found one I'm happy with I'll start thinking about bolting steppers on to my lathe.

Ian

[ptjw7uk]

Hi Saxonhawthorn,
Have a look at this one (free) http://doublecad.com/Download/tabid/1128/Default.aspx at bottom of page the free one.
I just remembered I had loaded it and have just tried it, looks OK but like any of the others will take time to look around, spent 10 minutes trying to find the ortho button.

Peter

[jonm]

hi
have you heard of the cnc toolkit,a plugin for gmax which is a free version off 3ds max , can make toolpaths from objects made in gmax, and generate g code all for freehttp://www.cnc-toolkit.com/
a manual for cnc toolkit can be downloaded here http://www.cnc4free.org/

[saxonhawthorn]

My word! You gents are all extremely helpful. The http://www.cnc4free.org/ link is a very useful one Jon, and seems to have the right philosophy for me now that we have to live on my meagre pension, namely: "If it costs money, we don't do it."

But looking at some of the lovely things people have made, I must say I am beginning to get the CNC bug :)

Ian.

[saxonhawthorn]

Thanks for the link Peter. I have downloaded DoubleCad, but I hope the product itself was not written by the person who wrote the download form. It demanded from me a company name I haven't got; then even worse, demanded that I tell them the most-used CAD packages in my non-existent company, offering me a list to choose from, most of which I had never heard of and none of which I have ever used, without even thinking of giving me a "none of the above" exit from the input loop.

This is an appalling way to write any code. I spent 25 years writing software for a living, and one thing I learnt from that is that more than half your code space (and programming time) is taken up by exception and error handling; i.e. when the real world (or the end user) doesn't do what you think it's going to do. I shall look with interest at DoubleCAD, but I hope it's error handling is better than that on their web site!

In the bath this morning (which is where I do my most productive design work) an approach to the expensive software problem occurred to me which I need to experiment with. It may be of interest to others here, and if so I'll post details when I've tried it. Won't be until after Christmas though; too much needs to be done in the workshop first.

Ian