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Cincinnati 500 arrow look ahead issue

ukkie

Plastic
Joined
May 29, 2020
Hi Guys,

Im wondering if anyone on here is running an old Cincinnati 500 arrow mill? We purchased this old machine a few months back and have been fixing the issues ( pumps, Spindle bearings etc etc). Anyway shes up and running and all looks good, however when it cuts using cam (fusion 360 with a direct link) she leaves a very poor finish on the floor of pockets. Im thinking there is a look ahead issue or piece of code that isnt quite right. The machine didnt come with manuals so its all abit of guess work, however a standard fanuc post seems to working efficiently enough. I think if it could do look ahead it would run alot smoother and not be so jittery when cutting. Does anyone know how I could turn this on in the machine or code??

Cheers
James
 
As to finish on the floor of a pocket, I have to agree, that it may not be look ahead related. You may not be leaving enough material for finishing, running out of spindle speed, improper tool, etc.

As far as machine tool jitters go, you're using modern software with high speed machining capabilities, to program a 30+ year old machine tool with. You will most likely have to alter your programming techniques to suit the machine's controller.

I have older machines and I use programming methods that are tailored to their capabilities.
 
Hi Guys, Its not that I'm blaming the look ahead for the bottom face ( the operation was also only a roughing cycle) but the finish was so mottled that it looks like this is caused by the machine trying to read code quick enough and causing data starvation . The bottom finish shouldnt look like it does from any machine even on a roughing cycle. Its that bad it almost looks galvanised! We have installed brand new super high precision bearings throughout ( almost the cost of the machine!) and the spindle seems to have next to no run out so I don't think its mechanical
As for the programming and speed, we have turned this right down for testing. We have set the cutting feed rate to 800mm/m and we have set the smoothing to .9mm to reduce the number of lines and points within the code which is the highest we can do on the software. Im not sure the software and cutting process is the issue, it just seems like some sort of look ahead code is missing as it is very juddery when trying to read code. It might be missing something very simple, as i said it was just a generic fanuc post ive tried..
 
I have spare touchscreen's, servo drives, spindle drive and other misc spare parts if you need anything.

I also have manuals and schematics I can reference if you know what info you are looking for.
 
What control is on the machine? And what options?

I run an Arrow 2000 with acramatic 2100 and have absolutely zero issues with high speed toolpaths from fusion/Inventor CAM.

Regurlary running 1500-4500 mm/min feedrates and no jerks or stops without any smoothing. In fact I noticed it runs better/faster with only lines and no arcs at all.

Lookahead of 2100 is 120 blocks if I remember correctly.

A picture of the surface in question would help a lot.

EDIT: Aha never understood that you're drip feeding. That might be an issue but as I said, a picture of the finish and what control model would be helpful.
 
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As for the programming and speed, we have turned this right down for testing. We have set the cutting feed rate to 800mm/m
I wouldn't call 800mm/m feed rate "turned right down". At that speed and small moves, it's going to be hard to keep data up to it at the max Baud Rate of that machine, probably 9600 Baud. I suspect, as others have mentioned, that its data starvation.
 
Hi vancbiker..the finish is better when running it manually. It seems to be better when running a short hand written program
Both help point to data starvation while drip feeding causing some jerky motion. I have drip fed some 3D surfacing code on my Mori Seiki where ~20IPM (500mm/min) was the fastest I could run without starving.
 
I have spare touchscreen's, servo drives, spindle drive and other misc spare parts if you need anything.

I also have manuals and schematics I can reference if you know what info you are looking for.
I am looking for a CRT for my avenger lathe and arrow mill. How much are you wanting for one?
 
I am looking for a CRT for my avenger lathe and arrow mill. How much are you wanting for one?

The ones I have are touch screen, I have the cinci parts in a thread linked below if you are interested. I don't want to get the moderators after me for selling in a tech help thread.

If you have any questions, feel free to reply to the thread below or send me a PM. Thanks!

 








 
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