Denford Software & Machines

Hello again, after a small break I have now been doing some jobs on the Triac again. Working well at the moment.

However one thing which puzzles me is the drilling cycle.
When drilling a series of holes each hole becomes shallower in depth!

any ideas

Programme as below

G00 X0 Y0
G01 Z0 FZ200
G83 Z9 FZ200 C1
G00 Y-25
G00 X25
G00 Y0
G80

Thanks Roy

what about the obvious - the drill's moving

Thanks, For that!!, But That was the fist thing I checked!

I Should have mentioned that in the first post and it was not moving, So any other Ideas ???

Thanks, Roy

Ah good!

I guess it's not a Fanuc control then?

cos The code ain't fanuc, maybe the feed is to high & the stepper is loosing steps how big is the hole (dia) try halving the feed.
going Z0 then Z9 to me is going away from the job Z0 = job surface & negative is normally into the job - but then if its not fanuc.... & whats that C1 I don't regognise that though I've not looked a the reference book so...??

It is a PNC controller, Its drilling cycle is slighty odd anyhow as you need to put Z as a positive to to achieve a minus! Also it drills the depth (in this case 9mm) from where the G01 Z0 FZ200 line is! So if G01 Z3 it would drill 9mm from 3mm above job

The 'C' is cycles, So In Fanuc terms 'Q' number of pecks.

Only an 8.5mm hole feedrate etc is fine, It drills a treat if i programme longhand, just can't figure out why the actual drilling cycle does not work!!

PNC urrrgggghh
well I've been forced to look in the fanuc book. G83 is peck drilling cycle so perhaps somewhere something is wrong with the peck distance or retact distance:?

perhaps it's a PNC "feature"

have you tried G81?

Perhaps Mr Magoo will have further insights I'm sure he knows the quirks of these controllers

Love to be able to use G81

BUT, As its a PNC, I am stuck with only the choice of G83 , Unless I programme longhand.

G81 is there.

Repeat function.

ok. I know it's a PNC box .... but I asumed that G81 would be the same(ish) in fanuc speak it's the same as G83 but without the pecking, i.e, doesn't do a retract to clear the swarf

oh and Q in fanuc terms is the depth of cut for each cutting feed - but then that's irelevant to you.

when you use G83 does it indeed retract to clear the swarf? In fanuc the retract distance is set in a parameter not in the code, I just wondered...

where's Mr Magoo when you need him?

G83 Does retract to clear swarf. You set it in the programme how many times you want it to retract.

Cutting edge stuff this PNC

G83 Does retract to clear swarf. You set it in the programme how many times you want it to retract

as per fanuc but the retract distance is in a parameter not in code

Hi Guys...

Just caught up with your posts.

Check if the display is reading correctly but the tool is mispositiong - this way you'll know if it's the steppers loosing position or the control s/ware misbehaving (although I think the terms "grandma" and "sucking eggs" could apply here ).

There is something in the back of my mind about a problem with a version of PNC milling s/ware that gave this symptom but I can be sure. I'll take a look in my archives & let you know if I find anything.

There is something in the back of my mind about a problem with a version of PNC milling s/ware that gave this symptom but I can be sure.

There I said perhaps it was a feature

Thanks Mr Magoo,

Your second idea seems to be more likely, as if i programme a 'new' drilling cycle at every position. I have no problem!

But obviously this is rather long winded!

I will await your findings

Roy

Sorry if this is a daft question:

Can't you just create a 'long winded' program from a CAM system, and dump or drip feed it into the PNC ?
Or are you just being a CNC purist ?

Having a quick look you are doing everything right so I I agree with Whizz, this is a 'special feature' in your version of the firmware

So I don't have a solution but would be interested to see if the symptoms change if this part of the program is in incremental - it may even work OK

Another one of the PNC's 'Special features' then!! Thanks Magoo, I will try it in Incremental just to see!

Admin, Creating a 'long winded' version is what i intended to do anyhow, as i am using a cam system, so just need to alter the post to suit.

But as the G83 drilling cycle was there, i thought i might try and make use of it!

Roy