Instrument maker

[Boyan Silyavski]

Thanks for all this info everyone. This is so valuable for me.



Does this mean, I'll be spending a lot of time getting the right toolpath and speeds etc, and eventually I'll have a program which I'll be able to keep using for one particular design?

It means you will start cutting fast, then lower speeds when you encounter problems. It also means sometimes instead of profiling, you will have to pocket some extra pockets, so as the rests from wood not to obstruct the vacuum shoe, or chip when they fly away. Meaning last pass should be carefull and well thought. / Lastpass is when you cut off the detail/ . As i said experimenting should be done with each material for optimum results.

I'm also interested in trying out many designs, timbers to see what effect it has on the sound.

Thats the spirit

Yes, it does seem loud. I'm wondering if I can use my machine at home during the day without too much extra soundproofing.

Forget about that

I know how to soundproof, so its not the end of the world, but it would be great to be able to occasionally leave a window open :-)

Its not the machine that makes the noise. Its virtually silent with the water cooled spindle. you can not hear it if you are doing sth small. Its the bit in the wood that makes the noise. A big noise. No windows open. For home scenario, you need a to make an enclosure. And if you have neighbours touching from one side, forget about that too. Even the frequent vacuum cleaning will make them crazy.

[JAZZCNC]

So i don't see 100kg gantry on small machine moven by steppers at that speed. Not to speak of 200kg gantry on 8x6 machine. From what i have read in forums and builds i have looked and studied, people using steppers normally achieve 5000-mm min on a normal build and 10 000mm / min on the better thought builds. I doubt that this 10 000mm /min is really usable with good acceleration on actual cutting, not rapids.

Boyan you are correct that machine with 100kg gantry won't reach 16,000mm/min with steppers but at 100kg it shouldn't be fitted with steppers so should be no surprise.!!

That doesn't mean correctly built and spec'd machine using steppers won't reach 16,000mm/min. most of the routers I build range between 600x400 and 1250 x 700 region and just about every one will reach those speeds. While testing/setup I push them to the extreme limit to find the saturation point where they stall and 20-24mtr/min is not uncommon.
Yes they don't get run at those speeds and I'll whind them back to between 10-15mtr/min rapids. All will happily cut at 10mtr/min if the tooling and material allow for it.

Servos are ok but as you know they also come there fair share of issues and requirements. Servo's while being stronger are not always better and in DIY enviroment mostly not required or recommended. KISS is the key at DIY level and steppers tick all the boxs. Servo's can quickly crush the boxs and frustrate the hell out of people. Also the cost doesn't just stop at the Servo's because again as you know suitable controller and all the correct cabling are required. (before you reply with "use chinese controller" not everyone want's to take this route)


Grambot:
Noise is big concern for most DIY users and can't be avoided because it mostly comes from the cutter not the spindle but it's simply case of enclosing the machine. Just make sure it's well ventilated.

Boyan the movement of your machine was nice to see but the trochoidal toolpath was IMO the wrong choice for this type of Job/material. It would have been quicker roughing in conventional manner then finish pass and much less stressful on the machine.

[Boyan Silyavski]

the way i see it :

long 3d toolpaths with serious material removal rate requirement → more spindle power needed hence 2.2 and even better 3kw /for home use/ → heavier and stronger Z with long travel /remember deep bowls/ → stronger gantry → heavier build → at least 70kg gantry with all mounted




Dean, i agree, The trochoidal path was only to test vacuum fixture, machine and board capabilities. I wanted to see what happens when cutter is routing full depth. Now i use again HSM technique, instead i changed depths with width and dont use trochoidal path, except for profiling the piece and also its only 3mm deep as deeper leads to chipping of edge. If that makes sense.

[JAZZCNC]

at least 70kg gantry with all mounted

Too many variables to say that. What size machine.? How deep bowl.? What material.? What cutter size/length.?
Smaller machine well designed can still cut deep bowls with good MRR and doesn't need to be weight of small tank.

3D work by it's nature doesn't have large step over so the cutting forces are low when doing the finishing. The bulk is removed by roughing so finish isn't important only tool life becomes a factor. So again well designed machine can handle this with good tool life but without being massively built.
Mass only really comes into play when cutting deep and requiring respectable finish without using finish pass. For any decent work that requires quality finish then machine weighing 20ton will still need light finish passes, infact several semi finish passes for some work.
The Massive weight is then wasted and infact acts like stone around it's neck. To move this stone is costing money.

So what I'm saying is while Mass is good sometimes it's not always benifical or required for certain types of work. IMO 3D being one of them.
You want fast moving machine that can take light cuts which doesn't require heavy machine and all the extra expense that goes with it.!

Strong doesn't have to mean heavy or like you seem to think and preach must be STEEL.!! Good design and Aluminium will work just as well.

I'll make this point Clear by refereing to 5 Axis JOBS Machine (costing £250,000 20yrs ago) which I nearly bought few years ago which originaly came from Mclaren F1 and used for machining the Steel moulds for there Composite parts. The WHOLE Z Axis which was over 1Mtr long was made from ALUMINIUM.!!!

[Grambot]

So, it seems that building a machine is the way to go here?

I'm wondering what the sort of costs would be for my needs - At least 500mm x 200+mm x 120mm, capable of +-0.1mm on wood and aluminium. And then some sort of enclosure, and dust extraction?

[Clive S]

So, it seems that building a machine is the way to go here?

I'm wondering what the sort of costs would be for my needs - At least 500mm x 200+mm x 120mm, capable of +-0.1mm on wood and aluminium. And then some sort of enclosure, and dust extraction?

Wal built a very nice machine here http://wrbl.tumblr.com/mill-build he is going to upgrade it with linear rails but have a look through his log and you will see the fine detailed work he has done with it.

[Ger21]

Don't forget that when you turn a big block of wood in to a bowl, you'll have about 20x (if not more) the volume you removed in the form of dust and chips.
Routers can make a huge mess, that can be difficult to contain at times.

[JAZZCNC]

So, it seems that building a machine is the way to go here?

I'm wondering what the sort of costs would be for my needs - At least 500mm x 200+mm x 120mm, capable of +-0.1mm on wood and aluminium. And then some sort of enclosure, and dust extraction?

Nearly impossible to answer accurately because don't know your skill level and how well equiped you are.
The cheapist way is to build frame using steel box section but this requires you are equiped with welder etc. Knowing how to weld also helps but believe it or not isn't exactly vital.? if your prepared to have a go then quite easy to learn with just few days practise.

There are some key areas on machine, like Z aixs that are quite difficult to make without some machining work so you will probably have to pay someone to do this if not equiped with machines to help.

Like Gerry says Extraction is Very important on router and even more important if enclosed. You'll need serious vacuum system if enclosing, little Henry type Vac won't cut it if removing large amounts of chips.

For Good machine with reliable quality components (not including Vacuum system) then you realisticly need to budget for Minimum of £2K with £2.5k being probably closer to the mark.
If your well equiped and can use your tools then along with some savy buying you can get this down.

What you MUST NOT do is Rush the build or be tempted to Buy Cheap Electronic kits you see on Ebay Etc. This is sure fire way to waste money and at best end up with under performing machine. Worst case you end up with Night mare basket case of machine which will deflate and turn you off CNC for life.!!
Doens't need to be this way and if you have patience along with the good sense to ask and listen then you'll build machine that will fill you with pride and put huge smile on your face.

Suggest you start looking around the Forum at differant machine style etc and read the Build threads front to back. Then start thread of your own outlining what you have in mind regards style and Components. Then when we will come along rubbish all your suggestions, kick it about bit, flip it, then Bing bang before you know it you'll have Cunning plan and away you go.!

The secret to SUCCESS is NO BUYING, NO RUSHING and most of all NO SHERKIN.? By this I mean do the research, learn whats needed and don't try to take short cuts. Design the machine Make Plan then Start building.

Don't be afraid to ask any question no matter how stupid it may seem. We ALL will have asked it at some time.
No one here will Mock or berate you for Stupid question but we will take the Piss out of you if don't ask it and get it wrong. .

Go for it don't be afraid. BUT be HONEST WITH YOUR SELF, Ask self if sure you have the skills and mind set to do this. . . . If not you will Fail.!

[Grambot]

Routers can make a huge mess, that can be difficult to contain at times

Good point Gerry, so I'd also need an enclosure, for mess and sound

Nearly impossible to answer accurately because don't know your skill level and how well equiped you are

My skill/experience is zero, but I'm a good learner when it comes to making things.

My worry is that a) it may take me too long figuring out how to make a machine when I want to get on with using it, and b) when I do make it, as its my first attempt, I may make mistakes, resulting in loss of accuracy.

I think I'm going to ask someone to make a decent machine for me!

[mekanik]

Hi
There is a wealth of information on the forum in the build logs, and the guys will help out with any problems but in your situation it could be prudent to have one designed and built by one of our forum members (if not snowed under) Just place a request in the FREELANCE JOBS AND REQUESTS section and someone might be a able to help.
Rergards
Mike