[hacdlux]

I'm having bar feed problems running 5/16 delrin

bar feed is a fmb turbo 3-38(20 mm channel installed)
machine is an tsugami ss32 running 6000 rpm

all was running well, and i didnt have to open the door for 4 days

then my feed collet broke a leaf off,
i had a spare hardinge collet that didnt work at all(feeder would get to 17 inches and stop making parts,
i ordered another fmb collet and had it overnighted

now i get all the way through the bar but i get a failure on remnant return. the remnant is stuck at the main collet.

running plastics- they either run perfect or you want to bbq the machine in the parking lot

[carmstrongls1]

sounds like a torque setting is too high. On plastics I take the standard calculation (for every 1mm stock diameter = 1% torque E.G. 20mm = 20% torque) then cut it by half. The integrity of the delrin or lack of will cause whip. When the collets hit the Spindle ID they heat up.

[hacdlux]

i've never heard that calculation before, yes there is a lot of whip

i'm due for a change in a few minutes i'll clean the machine out and try 4% (and yes i was running 15-25%)

problem being the guide bushing is running loose to accomidate the variations in plastic so i might start getting short parts again

[hacdlux]

now i'm down to 2% and i added another rechuck to the end when my sub is holding the part

now when i stroke check at the start of program it is actually pushing the bar into the cutoff(good thing)

i still get whip but i have a feeling thats the nature of having 4 feet from steady rest to collet.
i'm thinking of moving my main spindle to the back of the stroke (13") closing the gap between steady and collet but i think it might screw with the part having such a big gap between collet and guide bushing

part is only .312 long and delrin is cheap

any thought woud be appreciated

[carmstrongls1]

Chuck the hell out of the delrin. THen run the GB snug as comfortably possible. I ran tons of delrin before on swiss. I had an L-20 dedicated to Delrin production. All the doors and gaurds removed with vaccums on the spindle and tool blocks. Using stainless clamps with holes drilled in them.

[carmstrongls1]

your parts .312 long... Are you running a L. Hand cutoff? If not then set your machining data super tight. Like: Part length .500" as tight as possible. If not successful try the opposite and set it like 6" long. THen you risk the bowing effect between the GB and the front of the collet.

[carmstrongls1]

your parts .312 long... Are you running a L. Hand cutoff? If not then set your machining data super tight. Like: Part length .500" as tight as possible. If not successful try the opposite and set it like 6" long. THen you risk the bowing effect between the GB and the front of the collet.

[hacdlux]

im runnin aplitec 751 2.0 cutoffs which is a lh(sub side) cutoff in this machine

now my partoff is more like the std pull i use on my mori so the sub is maintaining my length perfectly

ive dropped my speeds to 3000 rpm

still having problems with the bar pulling out of the feed collet

[danrudolph]

Perhaps order an undersize barfeed collet?

We, through a screwup, bought a .295" bar loader collet for running 5/16" Delrin bar. I've never had one pull out of the collet.

Since you're on a 32mm machine, want to trade me the delrin work and for all my long 3/4" 304 and 316 SS jobs I have?

[hacdlux]

my former apps guy said the same thing about the undersize collet, i did a .257end prep on a short bar thats running right now and changed to a 1/4 collet i also left a .270 barb at the very end

were wrapping up this run tuesday, then i've got a stainless job, then an ultem job (all the plastic problems and it chews up tools)

most of these are parts for our own product but we do sub the machine out for guys that need the big bar, and i remember my last 304 and 316 jobs i got them running good just in time for the end of the run (highest qty was 40 parts)

[carmstrongls1]

Typically there is a standard machined in "interference amount when the BF collets are manufactured.

But many times you can find loose screws at the headstock sync device when this is happening. I recently had this situation happen in my shop with a second generation C-320 Edge barfeeder. Nightmare. WE replaced the logic, The PLC, Clutch brake assembly, THe engineers even came to my shop from edge and for two days we couldn't find it.

The day they left I found the belt connection block has a set screw that holds it through the bar to the main headstock. It was loose. Voila. So check there. May be a small problem.

Another thing as we spoke yesterday. THere are torque and speed settings to play with. Look in your manual and see if there are default settings you can revert to. THen adjust from there. One setting at a time.

also what diameter is your BF collet OD?

What machine are you running?

Excuse me if you already mentioned it.

[hacdlux]

after talking with my bar feed guy he said under 20% and it wont do anything
he also had me change the speed settings

i know all too well about the sync bar being loose one of my former helpers left the bolt loose and a couple days later i was pulling my hair out with short parts it is now one of the first things i check when it starts misbehaving

its a tsugami ss32 and a fmb turbo 3-38 running a 20mm channel
one day i wil convince the boss to get me a 10mm chanel for all the small crap i run

it was changing bars this morning when i left(flu) but i just got a call that its jammed....such is life