Thread: Instrument maker
My last advice before you jump in ordering a machine is have in mind the following:
That below will be your main tool/s in this kind of job/ there are cheaper variants, dont worry but i am speaking about the size here/
So start backwards from there. What spindle you need for that bit, what speeds the machine to move, how will evacuate the chips produced and so on.
Download HSMAdvisor, It has trial though i greatly advise to buy it, as it starts to become indispensable tool for me and if one knows how to use it it will save a lot of money, even when designing a machine. After my recommendation now there are all the chinese water cooled spindles included there. So choose 2.2 and 3kw spindles there, input the above router bit and start playing around so you see what happens. Change machine max achievable speed and so on.
That's how you will make really educated decision on spindle size, machine max speed, rigidity, motors and so on. Knowing exactly what final purpose is, how good a machine could be and how much will cost you that. Find the acceptable point that all is valid and seems good and that's it.
But i will tell you one thing from recent experience: Its good to have a very capable machine even if you don't know how to use it at first. Cause when you learn, there will be nothing to hold you back. Same with music. Any teacher will tell you to buy the best instrument that you could afford.
Yes, I agree, I want a machine which would enable me to grow in the future, and experiment with new designs. And I'm impressed by just how strong your machine looks!
You said in the description that it achieves 0.1-0.3mm accuracy - is that good for a DIY machine? I would really need no more than 0.1mm, because the parts I'm making are so small and complex, and often, several parts need to fit together in a moving mechanism. The more accurate they are, the better the finished instrument.
I'll have a look at HSMAdvisor, thanks for the link
It achieves 0.01mm not 0.1mm . But without too much over complicating stuff for you i will say that this machine is good for 0.05mm precision jobs or better.
Wood will change its size immediately after the cut, if there is humidity change or similar. Wood is not ideal, even when i cut it to 0.01 now on the machine, its has some flaws that need sanding and polishing, so final piece of only perfect material could be brought to such tolerances. Dont bother about that, we talk here about plastic and aluminum, when we say values under 0.0x
Here is an example. I work mainly with pine. No hard woods in my case, but otherwise some of them really hold that 0.01 precision after machining and can be machined to almost perfect finish.
On a slow machine that below / roughly 200mm diameter, 18mm thick overall/ could take 15-20 min to machine. As you not thickness is exactly 6.5mm.
But later it will need sanding, otherwise i could have machined it straight to 6mm from the beginning but it would have taken a lot of time to almost same finish as sanding it for just 1-2 minutes . So not worth machining it too much. As sanding it is much faster.
So as you see it needs sanding, otherwise i should have wasted unnecessary time to change bits, slow the speed and so on.
But too fast is also bad. As the machine does not have problem to make it for 4 minutes but many pieces chip:
So a compromise time of 6 min. Where i offset profiling toolpath 5mm. So if it chips like picture above its no problem. Then i make another profiling toolpath that takes the last 5mm only. 1.5 min more, but its worth.
Even so, i leave extra 1mm because finnish is not perfect and when 2 pieces glued together and dry, then i take out the last 1mm on the sanding disk, where it takes mere 30 second using 60 grit.
So i could finish this perfectly from the beginning but i will have to tool change, use always sharp bits, use expensive bits. Now i use one bit for 100 pieces then sharpen it by hand using diamond plate. And sand paper finish.
But that said, just yesterday i spend 100 euro on a CMT exchangeable blades bit, which i will use only for finishing, so maybe i will take one operation out, from what i am doing now.
This is just an example. Hard woods as i said could be finished too a much perfect finish, but sometimes a compromise here and there should be made, depends what how much costs you. BUt to warn you from now that even on the best 3d job, after that you have to sand a lot by hand :-) to make it to a high standard
Last edited by Boyan Silyavski; 11-10-2016 at 11:04 AM.
11-10-2016 #25Good point Gerry, so I'd also need an enclosure, for mess and sound
11-10-2016 #26It achieves 0.01mm not 0.1mm
I'm really looking forward to trying out different speeds etc, until I find something that works for me...
Don't count on the enclosure to contain the chips. If you don't remove them at the source, and let them build up in the enclosure, they will cause issues with your screws and bearings, which you want to keep clean
Often they are much noiser than the machine doing the cutting.
Also with being enclosed you need to be aware of the danger Static electricty and fine dust. Together they can be quite dangerous.
I would say that 100mm hose extractor will do the job ideally.
There are 2 ways that to be done- high pressure and low pressure. In both acases its important all to be grounded or there will be an explosion from the static electricity especially if a plastic job is done. And believe me even the shock from it is much greater than the typical static shock we experience entering or exiting cars or similar
The cheapest high pressure is 1000W and around 100 euro/gbp here or similar. Problem is high power consumption and noise.
If i was going that way I would rather buy 3 stage vacuum motor and design a simple enclosure to silence it mounted directly on top of separator on top of 200l barrel. I have done that in the past and works like a charm. The separator and enclosure is very simple to design and make from MDB
here is the motor:
Problem with the above is they make noise, so have to be isolated and they have high power consumption, plus have to be ventilated outside otherwise they heat the room much.
CLARKE Woodworker DUST EXTRACTOR 1hp could be the other solution. Again separator must be build on top of the barrel as there are no cheap ones for 100mm hose size/ if any/ . The original bag is crap, it will not collect fine dust.
I am in from of the same problem now and for the moment i use a shop vac and dust separator on top of 200l barrel. I don't like it for the high power consumption, small diameter hose and the noise.
I am thinking also about a smaller wattage tangential motor like 350W mounted on top of DIY separator on top of barrel. My friend has the same setup and reports its good. I will go these days at his shop to see with my eyes if small motor could evacuate the fine dust and small chips.
Last edited by Boyan Silyavski; 12-10-2016 at 10:03 AM.
I'll add to the advice above by saying hardwoods are not a problem and in my experience better to machine than softwood due to closer grain, more oils and hence less tearout, fraying and tool wear. An example of maple cut on my machine (the neck needed no adjustment, just a light tensioning on the truss rod to stop any rattle, and has not shifted since building the guitar in question):
Last edited by Washout; 12-10-2016 at 11:35 AM.My CNC Projects: https://www.youtube.com/playlist?lis...7_1sygWRSIBh_a
Great video Washout, with a lot of detail for someone like me to learn from, I'm watching more of your series now! I'll also be using hardwoods. Where do you source your timber? I'm going to need some quite large blocks to work with.
Boyan, thanks for all these extraction ideas. I've been speaking to Dean about making me a machine, and he agrees that with careful planning it should be possible to work out a solution to a) extra dust, b) keep noise down and c) keep temperature down. These are new challenges for me - I thought I had it hard being a musician trying to practice at home...
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