Diamondback S Air Requirements

[Nation03]

So in a quick turn of events, I may be purchasing a used 6 color Diamondback. I see that it's rated for 20cfm. If I were to have a 5hp compressor that runs 19cfm at 100psi would that still do the trick or am I going to have issues? I'll be running the press alone, so no where near full speed. Price difference for a bigger compressor isn't much but the 5hp motor runs on fewer amps and I'm a little restricted on power in my building.

Any help is appreciated!

[pwalsh]

When an equipment manufacturer states air requirements for an automatic press they tend to err on the conservative side.  For example the air requirements will be based on all heads operating with full length print stroke at the maximum rated cycles per hour for the press.  The reality more often is that the press operator isn't running all print heads, nor are they running the press at maximum cycle speed. 

The other issue regards compressed air consumption will come down to the type of compressor that you are running.  For example most Rotary Screw Compressors are rated at a 100% duty cycle (continuous running) while many piston compressors are rated at 70% or less continuous running.  If you're running a piston compressor you can even out some of the demand curve by installing an oversize air storage tank.

My advice is to keep a close watch on the incoming air pressure gauge to the press.  If you are starving for air supply you will see the pressure drop below the set-point while the compressor tries to catch up with demand.  This is important because air starvation will impact squeegee pressure and cause a variation in ink lay down.

 

[Croft]

I have for 10 years on my 6 colour air sportsman ,
A homedepot type 5 horse wont cut it they get too hot, i did use one but it only lasted about 1.5 years, I switched to a 5hp commercial grade piston type that worked perfect and was rated at 20 com, I switched to a Kaeser 5hp airpower about 2 years ago and it runs even better because it doesn't have the airdrop like the piston style.
20 cfm rating is if all heads are being used at the same time , which is pretty rare we occasionally will use revolver program with all 6 and haven't had any issues.

[Admiral]

I have for 10 years on my 6 colour air sportsman ,
A homedepot type 5 horse wont cut it they get too hot, i did use one but it only lasted about 1.5 years, I switched to a 5hp commercial grade piston type that worked perfect and was rated at 20 com, I switched to a Kaeser 5hp airpower about 2 years ago and it runs even better because it doesn't have the airdrop like the piston style.
20 cfm rating is if all heads are being used at the same time , which is pretty rare we occasionally will use revolver program with all 6 and haven't had any issues.

His servo indexer should help.

I think if you aren't going 100% speed and 4-5 screens the 5hp will handle it just fine.

Make sure there isn't all equipment running air at the same time if you are trying to go all out though.

[Nation03]

I got an Eaton Polar Air compressor. It is a piston style but it does have the option to have it run continuously which im sure would help the air drop. I don't plan on running it in that mode because I don't want the motor running constantly. It's rated for 19 cfm but some of the verbiage on the compressor says 24 SCFM @155 PSI. Not sure what the difference between cfm and scfm is but i think for my purposes, this compressor will suffice for now. 

[numbercruncher]

Somewhere years ago I copied this ....(not sure if it helps)
The difference between CFM and SCFM is in the simplest terms--- Well,  here's how you can state the difference . CFM is Cubic Feet per Minute, while SCFM is Standard Cubic Feet per Minute. 2. SCFM is the volumetric flow rate against a standard, whereas there's no standard for CFM. As a result CFM is usually less than SCFM.

[Nation03]

Yeah I read something similar to that but wasn't really sure what it meant.

I just confirmed with the compressor company the CFM rating. It runs 19cfm @175 psi and 24cfm @100 psi. I'm kind of a noob with this stuff.. Do I need to adjust the compressor to be at 100psi or is that controlled with that pressure regulator at the base of the press? Just want to make sure.

[Zelko-4-EVA]

you would adjust your compressor to the minimum pressure required by your press.

for example, i have a compressor rated for 175psi but my press only needs 110.  i would adjust the compressor to turn on when the pressure is at less than or equal to 110psi and turn off at 120psi. the regulator at the press would be adjusted to 110psi.