How about a mycncuk cnc router project?

[wilfy]

see when you start talking about code and toolpaths i get images of this marathon session of programming that takes longer than the machine does to cut

[JAZZCNC]

see when you start talking about code and toolpaths i get images of this marathon session of programming that takes longer than the machine does to cut

Well yes and no really. The drawing of the parts can be complex and time consuming but the process of actually getting code is easy really.

Toolpaths are the individual operations that make up the whole Code or G-code file. Changing parameters like cutter diameter for each tool-path is easy and takes seconds. The Cam software then just spits out new code to account for the new settings.

In the case of the Aztec calender It's just one large V-carving toolpath so literally less than a minute and new g-code file is produced. If needs re-sizing then it's 2-3mins.

[m.marino]

JAZZ is completely correct there. What takes time and really makes code generation easy is setting up your CAM program properly and making sure the post processor is set up for best practices on the machine. It sounds easy but takes time and a good bit of learning. Once set up, then it is simply import the model and run through the logarithm for that program (some area easier then others, all require set up). Back to the subject of discussion though.

A cnc router that cuts ally needs to be rather rigid to do the job with any kind of finish or speed (unless you want it running 18 hrs for a simple project). Let us look at some material issues and see why some many of us who are working with machines say no to too wide a range of use in a machine (though it can be done).

Material Issues:

MDF: when cutting this crap it creates huge amounts of TOXIC swarf that must be dealt with so you don't breath the crap (Unless you like killing yourself). The dust will try to get everywhere and takes forever to settle out of the air if an extractor set up is not used (dust shoe).

Softwoods: WILL dull carbide quickly, this is due to the high sap content of many softwoods and or grain structure. There are additional reasons that folks will most likely correct me on but this is one place where HSS-E rules the house not only in cleanness of cut but also finish left on the wood. There are exceptions in the higher end router bit and you pay for it.

Plastics: I really should break this down into sub areas but I am way to lazy right now and have other work needing done. Plastics come in a huge range of cutting requirements and all need the rigidity to get the best finish (any TIR will show in finished product). Most of them require care as are toxic to inhale and some you don't want the dust on your skin. Many are abrasive (Acrylic) and can eat your end mills faster then you think (there is a good reason to use coated). All of them have their issues and requirements on machining and all have limits at what they are good for (don't tap HDPE with anything less then M6 unless you plan on tapping deep). Some cut easier then softwoods and some you might as well be cutting ally.

Hardwoods: Bring a whole host of issues from grain direction to hardness to caustic. While more forgiving then milling metal they have all their own issues with many being rather TOXIC to inhale so back to the dust shoe issue again (one of the reasons that JAZZ like vertical machines as some of these issues go bye bye).

Ally: requires rigidity. For best finish requires reasonable DOC (deeper then 1 mm, unless finish surfacing pass and even then spindle power and rigidity are huge issues). Dry milling can be done at the right F&S's but best with coolant (now comes the issue of dealing with that, which I am not touching here). Spindle power above 1.5Kw highly recommended (though can be done with 1Kw, not the best for the motor).

Exotics: This includes PCB's, carbon GRP/FRP and a host of others. I have yet to meet one that is not TOXIC and most are rather nasty TOXIC and will KILL you if you breath the crap and some can go through your skin. All are moderately to heavily caustic and require coated cutters for best finish.

Other metals: a wide range of requirements that someone else can touch on as it is way beyond what a basic DIY machine of the less then £1K grp should ever be thinking about it being able to cut reasonably (I specifically exclude conversions of older equipment to CNC as you can get old mills and lathes that will do the job nicely and convert them to CNC).

NOW, take all the above and go look up cutwell and a few other sites to get a good grounding in F&S's and you will see why there are horses for courses and why the large gantry routers that due cut metal are huge and extremely rigid (surfacing mill I helped build in real work had a 15Kw Spindle and it's sole job was to surface bedding plates for building machines on ( it had a tool changer with only 10 tools) and had splash guards to three feet above the cutting area all the way around.

So step back and seriously think what you really want down and you can see that while an all rounder can be designed and built, it will have limits and only truly work for a few folks. Space and size as stated earlier are another serious issue.

I designed my machine and JAZZ built it with material help from more then a few folks. I use that machine in my business, it is continuing to be upgraded along the way for safety and increased output ability.

Just my two cents which is limited but has some practical experience behind it.

Michael

[GEOFFREY]

Hi, thank you, that is a most informative post. I think however that you are missing the point. When I made the original post it was about a small general purpose machine to help some people (generally diyers) get into cnc machine building and cnc machining. Once started (and they still have to build the machine), learn how to operate it etc. some people may well progress to building bigger better more specialist machines. Everyone starts somewhere, and surely if we can ensure that they have the option to build something designed with the input from knowledgeable experts (who may themselves wasted hard earned cash on the way) that can only be good. Just from reading posts on this site many have bought inferior kits/machines. I wonder how many are out there that are unaware of this site, and have have an unfinished or unused machine simply because it does not "do what it says on the tin", and probably never will.

The idea of this project was certainly not intended to discourage people from designing and building their own purpose made made machine, indeed I believe this is the best way to go, however for those with perhaps a little less self confidence, building a good solid starter machine could be the start of something special. G.

[D.C.]

TOXIC

So basically what you are saying is if you want lungs in your old age, pick another hobby?

Good job I'm not smoking a cigar and sitting under an asbestos roof, oh wait a minute... :(

[Web Goblin]

I think some people seem to look at cutting alloy as a type of benchmark for the machine. Maybe thinking that if it can cut alloy then it will do everything else they need. just my thoughts though.

[GEOFFREY]

Exactly, Thankyou. iWe are talking about a small robust starter project. If a machine that is primarily intended to cut softer materials is capable of ocasionally cutting ally, most people would indeed think it would cut almost anything that they would need to cut. G.

[HankMcSpank]

Yes, what is the fixation with cutting alloy....far better to build a machine specifically spec'ed to cut material you'll be working with 99% of the time (for me acrylic & copper clad FR4) - the other 1% of my cutting needs can be farmed out to those who are fixated with their machines cutting alloy ;-)

[wilfy]

Yes, what is the fixation with cutting alloy....far better to build a machine specifically spec'ed to cut material you'll be working with 99% of the time (for me acrylic & copper clad FR4) - the other 1% of my cutting needs can be farmed out to those who are fixated with their machines cutting alloy ;-)

you do know a previous post back there somewhere said if your cutting plastic you might aswell be cutting ally.... to quote

Some cut easier then softwoods and some you might as well be cutting ally.

[Lee Roberts]

Yes, what is the fixation with cutting alloy....far better to build a machine specifically spec'ed to cut material you'll be working with 99% of the time (for me acrylic & copper clad FR4) - the other 1% of my cutting needs can be farmed out to those who are fixated with their machines cutting alloy ;-)

Exactly, I’ve got just the thing to facilitate that coming up ;-)

Sorry you guys type faster than me so have said more or less what i am trying to say in my post above, i have to wait for spell checker to catch up :).

.ME