Author Topic: Going over to the dark (CNC) side!  (Read 23897 times)

Offline kuhncw

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Re: Going over to the dark (CNC) side!
« Reply #285 on: November 12, 2020, 05:16:42 PM »
Very nice work,Jason

Thanks for posting the steps you went through in the CNC process.

Chuck

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Offline Jasonb

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Re: Going over to the dark (CNC) side!
« Reply #286 on: December 31, 2020, 06:55:52 PM »
A while ago I asked whether anyone had used the tapered engraving cutters http://www.modelenginemaker.com/index.php/topic,8882.msg223889.html#msg223889

Well I've finally got round to trying out the ones I bought from Sorotec. Although a bit deeper than your average engraving my need was for some letters to apply to the side of a model to represent the cast on wording that would have been done with pattern makers letters. I found a couple of offcuts of soft bending brass which is a bit stickier to machine than the normal harder brasses used for machining and engraving so a good test for the cutters and with a thickness of 1.1mm a lot deeper than you would normally use them at.

To hold the sheet material I soft soldered it onto an off cut of 1/4" brass originally intending to just have a try and then do al the wording from a single piece but as the first letter went well I just squeezed the rest onto two smaller scraps. Taking the 60deg cutter with a 0.5mm flat end and running at 5000rpm and with a modest feed of 60mm/min and ramping down into the work at 2degrees for a max depth per pass of 0.25mm the cutters took it in their stride and seemed to produce a reasonable chip with minimal burrs left on the soft brass so I'm quite pleased with the result. After melting the work from the backing the letters just pushed out with finger pressure and a quick rub on some Emery had them ready for the next step.


I have been upto other CNC things some of which can be found in this thread.

http://www.modelenginemaker.com/index.php/topic,10064.msg229619.html#msg229619


Offline Alyn Foundry

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Re: Going over to the dark (CNC) side!
« Reply #287 on: January 01, 2021, 12:39:01 PM »
Your previous attempts went well at the foundry Jason.   :ThumbsUp:

Offline Jasonb

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Re: Going over to the dark (CNC) side!
« Reply #288 on: January 01, 2021, 01:53:48 PM »
Yes they look good with a bit of paint in the recesses, any sign of that flywheel yet?

Offline Alyn Foundry

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Re: Going over to the dark (CNC) side!
« Reply #289 on: January 01, 2021, 02:11:57 PM »
No, not as yet.

It's either stuck in the Christmas post backlog or they never sent it. Obviously I can't find out until next Monday at the earliest.

Cheers Graham.

Offline Jasonb

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Re: Going over to the dark (CNC) side!
« Reply #290 on: January 19, 2021, 01:22:05 PM »
Well with the post being what it is at the moment I decided to make a couple of Flywheels from Cast Iron, It was a good chance to try out the air coolant setup that I have been meaning to fit for a while. You can see the swarf build up on the ledges during the adaptive cuts as I was not able to manually clear it while taking the various video clips. But if you can bring yourself to watch through to the 5min mark you will see I have finally rigged up some air which is just enough to clear the swarf ahead of the cutter. The first side I stood over the machine clearing swarf more so on the adaptive than the finish but decided I did not want to waste another 3hrs each side. The second side and second flywheel were left unattended except for doing the tool change trusting F360 to have spat out the right code as each side and each flywheel was slightly different and all went well.

Ketan at ARC suggested that I use an air tool lubricator as I did not want to soak the place in coolant as this is what John Stevenson had set up ARCs own machines and his four Sieg CNC mills with. I'll only be using liquid when cutting aluminium but it certainly worked well doing the CI dry. Only a small amount of air is needed - the regulator was almost turned off and the swarf does not get spread all over the place staying in the "trough" that the KX3 comes with. I'll make the fitting a bit more permanent once I have tried it with liquid and then look at getting a quieter compressor as my old Machine Mart one is louder than the mill. The LocLine is acting as a means to position the air only as I have run a 4mm OD PVC line inside that with a small brass outlet drilled 1.5mm to get the velocity up and it will save a build up of fluid in the LocLine before it comes out the end.

« Last Edit: January 19, 2021, 01:27:09 PM by Jasonb »

Offline Steve17

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Re: Going over to the dark (CNC) side!
« Reply #291 on: January 19, 2021, 03:21:12 PM »
Jasonb, I like the idea of the tool oiler. What do you use in it? As in white water, cutting oil or any of the liquids designed for minimal quantity use. I purchased the last CNC from John's son last year and there is no sign of any retro fit coolant system.

Steve.

Offline Jasonb

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Re: Going over to the dark (CNC) side!
« Reply #292 on: January 19, 2021, 03:41:04 PM »
Ketan says neat cutting fluid but as I'm only going to be adding liquid for aluminium will give it  ago with paraffin first.

If that is the one I saw up for sale then I don't think it was one of the ones from JS's workshop that he used to knock out things like the Myford index plates etc.

I may still have some photos thatKetan sent, will see if I can find them

Offline Vixen

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Re: Going over to the dark (CNC) side!
« Reply #293 on: January 19, 2021, 03:49:16 PM »
Jason,

Do you still have diaphragm air-brush compressor that you could try? You dont need a high pressure or even a high flow to blow away the chips. Using a big shop compressor is overkill. The noise on my shop compressor kicking in unexpectedly, when I am doing fine work, always makes me jump.

Another possibility is a small centrifugal fan similar to the fan a blacksmith uses to stoke the forge hearth fire

Mike
It is the journey that matters, not the destination

Offline Jasonb

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Re: Going over to the dark (CNC) side!
« Reply #294 on: January 19, 2021, 03:57:37 PM »
No chucked that out years ago. Mine is the smallest of the Machine mart ones only 5cfm displacement so more like 3cfm FAD, I would say it's running 30% of the time. Regulator is screwed out as far as it will go, anymore and flow stops and not even registering on the pressure gauges so very little air being used. I would say it's no stronger than I can blow. The biggest problem is it's 95dB so I'm thinking of getting one of the "quiet" ones that are said to be 60-70dB with a larger tank too.

Picks of the setup on the one ARC use

« Last Edit: January 19, 2021, 05:39:38 PM by Jasonb »

Offline Muzzer

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Re: Going over to the dark (CNC) side!
« Reply #295 on: January 19, 2021, 06:05:29 PM »
The compressor on my machine is a Bambi - enough to operate the drawbar and gearbox but barely enough for constant discharge. I can use it to periodically blast chips clear but I need something better that doesn't require manual operation. I managed to break another tool last week due to it recutting (welding) aluminium chips, which is what has broken pretty much all the 3-4 tools I have lost over the last year or so.

I have an HVLP compressor from Screwfix that seems like an alternative approach . Rather than being a reciprocating (piston or diaphragm) compressor, it is a fairly compact centrifugal blower. Perhaps not surprisingly it sounds like a vacuum cleaner. It blows a strong jet of air and may be easier to quieten than a giant compressor, with the possibility of hiding it inside the body of the machine - once you strip away the giant plastic housing, the guts are actually fairly compact.

Offline Muzzer

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Re: Going over to the dark (CNC) side!
« Reply #296 on: January 19, 2021, 06:08:14 PM »
The compressor on my machine is a Bambi - enough to operate the drawbar and gearbox but barely enough for constant discharge. I can use it to periodically blast chips clear but I need something better that doesn't require manual operation. I managed to break another tool last week due to it recutting (welding) aluminium chips, which is what has broken pretty much all the 3-4 tools I have lost over the last year or so.

I have an HVLP compressor from Screwfix that seems like an alternative approach https://tinyurl.com/y4tex4ju. Rather than being a reciprocating (piston or diaphragm) compressor, it is a fairly compact centrifugal blower. Perhaps not surprisingly it sounds like a vacuum cleaner. It blows a strong jet of air and may be easier to quieten than a giant compressor, with the possibility of hiding it inside the body of the machine - once you strip away the giant plastic housing, the guts are actually fairly compact.

Offline Jasonb

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Re: Going over to the dark (CNC) side!
« Reply #297 on: January 19, 2021, 06:42:32 PM »
This is what I'm thinking of at the moment, you can get similar cheaper from unknown brands but at least this has a warranty and can be used for other things too.

https://hyundaipowerequipment.co.uk/air-compressors/hyundai-50-litre-air-compressor-1cfm-100psi-oil-free-low-noise-electric-2hp-hy27550/

Offline Muzzer

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Re: Going over to the dark (CNC) side!
« Reply #298 on: January 20, 2021, 01:09:32 PM »
They claim 60dBA which is a LOT better than the normal 90-100. Looks as if it perhaps has series diaphragm pumps rather than pistons. 1.5kW should allow you do use actual air tools too, as you say.

By way of comparison, the Bambi claims 40dBA - when it's running, it sounds like a noisy fridge, which is perhaps not surprising when you look at its construction.

Offline dieselpilot

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Re: Going over to the dark (CNC) side!
« Reply #299 on: January 20, 2021, 05:40:21 PM »
I have a California Air Tools 10020C which are available in the states. This one is a single 2HP pump. I think initially, all these pumps were made at the same place. The pumps seem reliable as some have run them well beyond the rated 3000Hr. The downfall for noise is they all include a standard pressure switch with an unsilenced unloader valve. Beyond the pump and switch, the rest of the components are cheap as can be. All connections had to be resealed. While the pumps appear to be on isolators there is a solid rod though the middle. Even on a concrete floor after adding real isolators I can feel the machine. My tank leaked at a weld for the motor bracket. CAT did replace the tank just outside the warranty period, but it seems a common failure. I had a very high duty cycle which meant problems with water, so I added an aftercooler. For unloader noise, I added a solenoid valve with a silencer. Cheap compressors are ,well, cheap. Unfortunately, the next step is a huge investment.

Maybe a Hyundai is better? I'd wait from some reviews if not in a hurry.

HVLP turbine is certainly less than 10 psi, cheap units probably below 5.