[Astro guy]

Hi all,

My company is looking at getting a Haas mini mill with 4th axis, so im getting together a final price of everything we need to get it up and running. Im struggling to find a suitable compressor set up to power the pneumatics on it though, witout paying a fortune, and if i cant keep the final price reasonable it might concievably affect whether or not my bosses go for investment in the mini mill at all.

So i guess what im asking here, is what compressor do you use to power your Haas? And what kind of ball park cost?

I know many Haas machines will have been fitted in engineering workshops that more than likely use large compressors to power multiple machines, but i noticed from a few theads on here before that some users have small workshop set ups, or even home set ups. This is more like what we have here as i work in the development and prototyping department, so need only a compressor to power the Haas, and maybe an occasional air tool in future.

All help greatfully recieved!

[Geof]

I guess costs are not completely comparable but I originally ran a Super MiniMill using a 12cfm piston compressor that cost about $700. This compressor was larger than needed and it may be possible to get by with slightly more than half that size. After a few years I did switch to a larger screw compressor so I could have an air blast for machining steel. This one is 18cfm and cost a bit over $3000.

[Astro guy]

Theres bound to be some difference in price, but so far i have struggled to find anything under £3000 here, as not only does Haas say it needs to be oil and moisture free, but we also need it to be relatively quiet too.

But even forgetting the issue of noise, the cheapest i have found is still over £2350, which seems a bit expensive for a compressor to run a mill!

The specs that Haas uk gave me were that it needs to have a minimum of 50L but preferably 100L tank or more, have atleast 2hp motor, and supply 100psi @ 6scfm. And obviously oil and moisture free - which is where the expense comes in.

Does that look roughly like what you were using on yours originally?

[Geof]

2350 does seem a bit high, based on my experience with prices over there I expected maybe double our prices. If that includes a refrigerated dryer then I can understand it.

My first compressor more or less matched the Haas specs because a piston unit can only be run on a 50% duty cycle so while it was rated at 12 cfm it was effectively only putting out 6 in the long term. It also had a 30 gallon tank so it was well over 100L.

Clean dry air is important, I found that out years ago when solenoid valves started acting up. I do not have a dryer but my air supply goes through over 100 feet of copper pipe so it is thoroughly cooled and I have a tank at the machine that serves as a water trap.

I will comment that I think you are looking at the cost the wrong way. You are not spending 2350 pounds on a compressor to run a mill you are spending, or will spend when tooling is included, somewhere between 35,000 and 50,000 to improve your productivety 5 to 10 fold over manual machines and give you the ability to make things that are simply impossible on standard manual machines. In my experience the latter ability is the most important especially for prototyping.

[Machineit]

Theres bound to be some difference in price, but so far i have struggled to find anything under £3000 here, as not only does Haas say it needs to be oil and moisture free, but we also need it to be relatively quiet too.

But even forgetting the issue of noise, the cheapest i have found is still over £2350, which seems a bit expensive for a compressor to run a mill!

The specs that Haas uk gave me were that it needs to have a minimum of 50L but preferably 100L tank or more, have atleast 2hp motor, and supply 100psi @ 6scfm. And obviously oil and moisture free - which is where the expense comes in.

Does that look roughly like what you were using on yours originally?

I get the impression from reading your post that you are taking the phrase "And obviously oil and moisture free," too literally. It does not mean that you need an oilless compressor. There are such compressors out there, I have one at home, but they are generally smaller home models or big expensive commercial models. Most compressors are oil lubricated, but this does not mean that you will have a lot of oil in the lines unless the compressor is worn out with bad rings.

Although it is nice to have a dryer, it is not a necessity. I have run CNC mills for 20 years and have never had one myself. If you locate your compressor a good distance from your mill so the air cools down and plumb it correctly, you will have little or no moisture in the lines.

When you run your lines have them slope downward as they go and put a drain at the end. Where you put the connections to the machines and all, I turn them upward so no water can never run into them. I turn mine up about 45 degrees.

If you drain your compressor tank regularly and the line ends you will get pretty dry air. Regulators with oil and water separators on them are very inexpensive and will help keep the air supply clean. They even have automatic drain on them.

The size of the compressor you need is actually very small. My small compressor at home cost only about $250.00 and it is 5 hp and 5.5cfm at 90psi. That is plenty to run your mill on. The mill itself does not use much of a volume of air. It uses it for tool changes and the spindle lubrication system. The volume is less important than the pressure. You need to have the proper pressure for the tool release piston and that is the 100psi they call for.

The benefit to having a larger compressor is that it will run less often, runs cooler, cycle times are shorter and thus they last longer. I think they also have less of a moisture problem if they run cooler.

The bottom line is that you do not need some special type of compressor. A standard everyday compressor installed properly will work just fine.
after a number of years of retirement I am opening another shop next week and I will get a basic compressor to use.

One last note: When I install a compressor and I can't put it outside, I build a housing around it. Just thin plywood and then I insulate it will regular insulation. I put an exhaust fan in at the top that comes on when the compressor does and a vent on the bottom for air to enter. This insures that the compressor gets plenty of air for cooling. Make it large enough that you can easily service the compressor or even remove it if you need to. You will be amazed how much quieter it is that way. It won't drive you bonkers with the noise all day.

As has been said before, we don't know your prices over the pond, but here I can buy a really nice compressor for any number of locations for $600 to $800 and it will have 4 times the capacity that you need. Also that occasional air tool you mentioned will use 5 times the air that the mill will.

Sorry for the long post, but I hope that it helps you decide.

Cheers----MIke

[l u k e]

Clean dry air is important, I found that out years ago when solenoid valves started acting up. I do not have a dryer but my air supply goes through over 100feet of copper pipe so it is thoroughly cooled and I have a tank at the machine that serves as a water trap.

What type of copper pipe did you use, is it just water pipe with soldered connections?

I did install a drier and have not got a single drop of water out of it, not one. I'm also a good distance from the compressor, I believe I ran 50' of 3/8 standard rubber/pvc airline. It’s run across the ceiling in my shop so it's an up hill climb almost ½ that distance. (Vaulted ceiling).

The main thing I don’t like about the drier is it constantly uses air and is always kicking on the compressor even if no air is being used. I may consider tweaking my setup some later down the road if I don’t actually start getting some water out of the drier when I really start putting the compressor to work.

[Geof]

Standard 1/2" copper water pipe with soldered connections. This is in my home shop but we use 3/4" copper at the production shop.

Where is your dryer in the system, between the compressor and the tank or after the tank? If you are not using much air and the dryer is after the tank it may not pick up much if any water because the air cools in the tank and everything condenses there. Our shop system condense some air in the tanks and then additional air in the dryers and both have electrically operated dump valves. My home system behaves much the same, some condenses in the compressor tank and then rest finishes up in the tank at the machine. I have my air gun connected to the drain on the tank at the machine so whenever I use it I empty any water out of this tank.

Try using air blast for machining 'dry'. You will soon find water being collected once you start using large quantities of air. Either that or you will get water out the air blast.

[l u k e]

The drier is over by the VF2, hanging from the ceiling, between the compressor and the mill. (I had the roof trusses designed to carry 2 tons at that intersection for pulling car engines, way over kill but I worked for the company )

I went out and looked at the hose and it’s a steady climb all the way to the drier, probably 35feet total, all up hill. Compressor is on one end of the shop and the mill and drier is on the other so it looks like there is plenty of time to cool the air down.

I don’t really like the drier because it uses constant electricity, it puts off a lot of heat which will be a bummer in the summer and it constantly uses air. I'll give it a chance to prove itself but I think by the end of the summer I'll be bypassing it with some minor changes and additions to the current setup.

[Astro guy]

Sadly geof its not my money being spent or id have it already as im in complete agreement with you! The thing is the mill will initially be used for mainly prototyping with a view to small batch production and customisation of existing designs for clients in future, so keeping costs low will help convince my bosses to invest now rather than wait.

I have recieved some further quotes from various companies, one for a small hydrovane set up that has all the filters/refrigerant dryer,etc. fully fitted for under £3k (an improvement on what i was looking at before) and another company has quoted a piston compressor set up for around £1500 not including fitment, but that might be too loud for where it will be situated as my workshop is directly below the main office and sales department, but its worth looking into.

Thanks for your post Machineit, thats exactly the kind of info im looking for, as frankly im a little out of my element with compressors and it gives me plenty to think about. Building an enclosure would certainly give me more options too as the noise issue kind of limits my options, and drives the cost up.

I think i'll put forward two options to my bosses, one for a higher spec set up and one that keeps costs low - then its up to them to decide which is the best option.

Thanks for all your help!

[JohnJW]

I am using a screw air compressor that is oversized for what I need, ~50sfm with a 120gallon tank running a single VF-2ss. Even though it's pretty dry in SoCal, I still notice moisture in the airline. Not a lot of moisture, but if I blow compressed air continuously on a piece of fabric I will see a damp spot after a while.

Anyway, I finally installed a refrigerated air dryer and it passed my crude moisture test and I don't hear the popping sound during tool change anymore.

For airline, I followed the advise from the forum and just solder together regular M type copper pipe from home depot.

[KenFoulks]

The drier is over by the VF2, hanging from the ceiling, between the compressor and the mill. probably 35feet total, all up hill.

All of the water is pooling in the pipe by the compressor. Water condensates and travels downward. If the pipe is small enough the water will be pushed through. In this case the air is traveling through the water and eventually the 35 foot pipe will fill and you will start to get a lot of water in your dryer.

Instead of the dryer, leech into the current setup at the lowest point by the compressor with another pipe heading downward. Place a valve at the end of the pipe. Empty monthly.

[lkenney]

I ran my VF-0 on a Home Depot 5HP portable with a 30 gallon tank, IIRC it was about $250-300 when I bought it. I did setup a pipe drain cooling system and it worked pretty well. This compressor was able to keep up with all the air that was needed by the VF-0. When I wanted to start using more air I needed a larger storage tank.

I did buy a HF chill cooler for $120.00 when I put in a 5HP new compressor with a 80 gallon tank (about $750.00) so that I could CeraKote and machine at the same time. It has worked very will. We have a lot of moisture in our air here in Western WA most of the time.

We did build a room out the back of the shop to put the Air Compressor and the phase converter in. Made the shop a lot nicer to work in.

Lowell

[gizmo_454]

Wow...Lots of input here, for sure! I will add my 2 cents and get out of the way...

We have been using a 5HP Ingersoll Rand single stage compressor for the last 5 years. It is more than sufficient for one machine. We have been running our Mini Mill and an SL-10 on it, along with the rest of the shop. We just picked up a VF2SS and a Citizen swiss which kind of put the little compressor out to pasture. Never the less, a compressor of that size is more than sufficient for one machine. Price at our local Home Depot is $800-$900 US. Again, I don't know what the price difference is either.

You may want to consider a used compressor for a more reasonable price.

As to the dryness of the air, we didn't do anything fancy. We are using a coalescing filter and trap with an automatic drain. The filter, regulator, and trap run about $200 from TP Tools. The filter's element looks in passing like a roll of toilet paper and filters down to .01 micron. It was originally intended for use as an air filter for painting cars where water and other particulates are not wanted. The elements are cheap at about $5 each. Normally, we keep 3 or 4 on hand to change out on a weekly basis. When they dry out, re-use them. Usually our 3 to 4 elements last us about 5 to 6 months under production conditions, so for prototyping, they should last quite a bit longer.

I hope this helps. Good luck in your quest!

Mike

[mtlhe]

Here's a link to a USA made compressor company. We bought one a couple years back. The VERY best compressor we've ever owned. Outstanding company. Air Compressor Parts : Variable Frequency Drive : Variable Speed Drives : Piston Air Compressors : EatonCompressor.com

[dfurlano]

Wow...Lots of input here, for sure! I will add my 2 cents and get out of the way...

We have been using a 5HP Ingersoll Rand single stage compressor for the last 5 years. It is more than sufficient for one machine. We have been running our Mini Mill and an SL-10 on it, along with the rest of the shop. We just picked up a VF2SS and a Citizen swiss which kind of put the little compressor out to pasture. Never the less, a compressor of that size is more than sufficient for one machine. Price at our local Home Depot is $800-$900 US. Again, I don't know what the price difference is either.

You may want to consider a used compressor for a more reasonable price.

As to the dryness of the air, we didn't do anything fancy. We are using a coalescing filter and trap with an automatic drain. The filter, regulator, and trap run about $200 from TP Tools. The filter's element looks in passing like a roll of toilet paper and filters down to .01 micron. It was originally intended for use as an air filter for painting cars where water and other particulates are not wanted. The elements are cheap at about $5 each. Normally, we keep 3 or 4 on hand to change out on a weekly basis. When they dry out, re-use them. Usually our 3 to 4 elements last us about 5 to 6 months under production conditions, so for prototyping, they should last quite a bit longer.

I hope this helps. Good luck in your quest!

Mike

Mike,

I am using ARO 1500 filters (pre and coalescing) and I just bought the automatic drain but the strange thing I am not sure how they work. I assumed the automatic drain needed a value to pull a vacuum to empty the filters. But the ARO are different and I am not sure what else I need to get them to work. I looked on their web site and called them but no one could tell me how the work? They must have fired everyone with any technical knowledge.

[rawen2]

dfurlano,
I don't know how your auto drain filters work but the ones I've seen have a float inside the bowl. When the water or oil level rises enough the float opens a valve on the bottom of the bowl and the air pressure forces out the liquid.
Ralph

[dfurlano]

It was my fault. I added some water to the bowl and once you turn the air on blew out the water and shut off. When it was dry it just was blowing air and did not shut off.

I had Jun Air filters and removed them due to age. The Jun Air require a vacuum.

These are the ARO filters I bought with the automatic drain which use a float technology.

Compact Coalescing Air Filter 1/4"-Industrial Automation

Compact Piggyback Air Filter/Regulator-Gauge 1/4"-Industrial Automation