strange boring problem

[cherokeechief79]

I have some parts that im running that are giving me fits .

they are around 6 inches long and look like a dogbone shape.

there are 2 critical bores in each end at 1.000 1.0005.

op 1 cuts the top face and the complete outer profile at full depth.

at op 2 I flip them over and hold on the outer shape in softjaws.it cant really crush the part because the softjaws

hold the entire diameter including the bar in the center between the ends.

the 1st part cut nice in the machine and the bore measured out nice too but I only measured it in one direction.(stupid me)

I rough the id within .005 with an endmill and then use a very nice and expensive boring head with insetrs for the material im using.

with it out of the machine it measures .0008 out of round.

next part I stopped the mach at the boring op and loostened the jaws till it just barely grabbed and got the same result.

now ive got another one mounted and before I bore I put an alum clamp over the center of the part ant back the removable jaw off about .01.

in the machine I can see its cutting all the way around but its still about .001 out of round still on the machine!

I put a marker on the bore surface and took .0005 more out and could see it cut evenly all around but is still about .001 out of round.

at this point im at a total loss.

 

the machine is an older has vf4 and the material is titanium that was 3d printed.

the material machines ok otherwise but is a little rough on the tools im roughing it out with.

 

any ideas?

[absolute technologies]

If you have a precision test bar with the #40 taper shank you could check runout of the spindle. If not, then setup a test block that won't distort and bore an equal sized hole to see if it comes out round.  On some thin walled parts, regardless of light you clamp them it will still distort them.

 

Cheers!

Len Dye

[duckdogers]

that sounds like a machine issue but I have to ask,why bore and not contour cut the hole its a lot faster .I have never used a boring head yet

[cherokeechief79]

I just put a tenths indicator in the bore and its showing exactly what the bore gage shows.

the haas troubleshooting guide says the most likely cause is the spindle bearings.

while the indicator is in the bore I can grab way up by the spindle and push it and get a few tenths movement.

I guess I just picked the wrong machine in the shop to run this on!

 

im going to put a brand new finish endmill in and interpolate the bores.(wish me luck!)

 

there is a note that states we cant use any grinding operations on these parts. I think honing them is considered grinding.

 

ps.......the part is not clamped at all now just held downward with a clamp.

[cherokeechief79]

that sounds like a machine issue but I have to ask,why bore and not contour cut the hole its a lot faster .I have never used a boring head yet

 

its our oldest machine in the shop I thought I could do this best by boring the holes.

there is also a very tight tolerance between the holes.

[mkd]

being that you are just getting this going, is there a chance you have positioned over the hole from different directions?

i like to use G60 G61 for the first hole to make sure i come at it consistently.

 

 

this topic should be moved to the machining forum.

would be easier to tell if the industrial forum was titled better.

[specv]

Is the roughed hole round? I think that may be the issue, also you said you mill it within .005 is that total or per side.

[cherokeechief79]

Is the roughed hole round? I think that may be the issue, also you said you mill it within .005 is that total or per side.

the roughed hole is undersized by a total of .006. 

  .003 per side and is perfectly round.

that's why I have confidence in interpolating it now.

I changed it over already and will start again in the morning.   (ill be on the clock then!)

 

these parts are titanium and the 1st production run off of the 3d printer and I was wondering if there were some type of strange stresses in the material but im pretty confident its in the bearings now.

when im done with this ill try the same thing on a pc of aluminum .

[gcode]

I don't think you will be successful on this old Hass

IMO you should move the job to a tighter machine

[cherokeechief79]

I don't think you will be successful on this old Hass

IMO you should move the job to a tighter machine

sounds easy but 20 of these parts have to be in QA on Monday morning.

that only leaves me 8 hrs tomorrow.

the print also requires a special type of coolant and the machine was flushed and filled with this new stuff!

[mkd]

I don't think you will be successful on this old Hass

IMO you should move the job to a tighter machine

:realmad: i heard that!

 

 

double check your setting #57 on Haas for canned cycles. Needs to be on.

 

op 1 cuts the top face and the complete outer profile at full depth.

at op 2 I flip them over and hold on the outer shape in softjaws.it cant really crush the part because the softjaws

hold the entire diameter including the bar in the center between the ends.

 

dont be so sure the shape you are programming is actually being inparted to the outside of the part IN TITAINIUM. (how many finish/spring passes with a finsher?)

If it were me, i would relieve the jaws around where the precision bores, as it sounds like you've already discovered some distortion.

[cherokeechief79]

:realmad: i heard that!

 

 

double check your setting #57 on Haas for canned cycles. Needs to be on.

 

dont be so sure the shape you are programming is actually being inparted to the outside of the part IN TITAINIUM. (how many finish/spring passes with a finsher?)

If it were me, i would relieve the jaws around where the precision bores, as it sounds like you've already discovered some distortion.

setting 57 is off. ive never messed with it.what exatly does it do?does it make sure its in xy position? does it add time to a programmed part?

when I rough the outside of the parts I use a carbide rgh mill,a semi finisher that leaves only .003 and finally a very good carbide endmill just for titanium.the widths I can measure are exactly the same so far on all 20 parts ive done without comping anything at all.

[gcode]

:realmad: i heard that!

 

 

 

 

and you know it's true 

[taperlength]

Might be able to comp the bore in two halves and tweak the location of each half to get a bore in tolerance.

[civiceg]

Are you using a G86 to bore?

[mkd]

setting 57 is off. ive never messed with it.what exatly does it do?does it make sure its in xy position? does it add time to a programmed part?

when I rough the outside of the parts I use a carbide rgh mill,a semi finisher that leaves only .003 and finally a very good carbide endmill just for titanium.the widths I can measure are exactly the same so far on all 20 parts ive done without comping anything at all.

#57 adds goodness to hole cycles.I have no idea why Haas would ship their machines with that turned off. I recall struggling with true position at an aero shop in the late nineties I had just started with. Turns out things improved after turning that little rascal on.

 

and you know it's true 

hey man, not everyone can be a evil rich guy, running okuma 5 axis with FIVE DECIMAL PLACE ACCURACY

[jlw™]

Somebody's gotta fill me in on that 5 decimal places accuracy jab. So, who was kidding when that got started?

 

Is that five decimal place on paralosity or truism? (I've heard both of those recently)

[Thee Awbade™]

#57 adds goodness to hole cycles.I have no idea why Haas would ship their machines with that turned off. I recall struggling with true position at an aero shop in the late nineties I had just started with. Turns out things improved after turning that little rascal on.

 

hey man, not everyone can be a evil rich guy, running okuma 5 axis with FIVE DECIMAL PLACE ACCURACY

I don't get the jab, but I saw a Kuraki HMC last week that was getting true positions within a millionth. (On a rebuild Job.)

[cherokeechief79]

ive got it going to get this batch out but what a pain.

I leave .003 per side with the 1st rgh tool and  then finish the id with a brand new 7/16 em just for titanium.

the 1st part came out .0004 out of round and my tol is just .0005.

It was large in the direction of my lead in and out.

I also overlapped by .100.

so now I do one pass leaving .0005 on the wall and then I take another pass at "0" but on the 2nd pass I moved the lead in and out 90 deg.

its a horrible way to do it but its reading round within .0002 now and seems to be holding size.

[mkd]

Somebody's gotta fill me in on that 5 decimal places accuracy jab. So, who was kidding when that got started?

 

Is that five decimal place on paralosity or truism? (I've heard both of those recently)

 

 

I don't get the jab, but I saw a Kuraki HMC last week that was getting true positions within a millionth. (On a rebuild Job.)

holy moly^^

 

apparently, i'm not nearly as funny as i think i am....and if you have to explain a joke, it definitely wasn't 

 i thought it was kinda obvious with the Jab against the best brand (haas) and the super awesome science-project- level 5 axis that our esteemed brother gcode programs. It's position display doesn't stop at 4 decimal place like most CNCs; it goes to 5

:sulk:

[mkd]

ive got it going to get this batch out but what a pain.

I leave .003 per side with the 1st rgh tool and  then finish the id with a brand new 7/16 em just for titanium.

the 1st part came out .0004 out of round and my tol is just .0005.

It was large in the direction of my lead in and out.

I also overlapped by .100.

so now I do one pass leaving .0005 on the wall and then I take another pass at "0" but on the 2nd pass I moved the lead in and out 90 deg.

its a horrible way to do it but its reading round within .0002 now and seems to be holding size.

for a machine rated @ .0002" positional accuracy (or .0004 for an interpolated circle) that's not entirely surprising. I can hold tenths on size and roundness on mine without any special gymnastics other than sneaking up on it more than premium brands.

[mmack]

are you using a balanced boring head ? have you tried adjusting the rpm ??

[cherokeechief79]

so I got the 1st batch of these out and decided to try an experiment.

I took a pc of aluminum the same thickness a replicated everything I did in the additive manufacturing titanium parts.

I left the same amount per side for the boring operation(.002 per side)

this time the bore came out perfectly round!

not even one tenth out of round.

it must have something to do with these printed parts.

[crazy^millman]

so I got the 1st batch of these out and decided to try an experiment.

I took a pc of aluminum the same thickness a replicated everything I did in the additive manufacturing titanium parts.

I left the same amount per side for the boring operation(.002 per side)

this time the bore came out perfectly round!

not even one tenth out of round.

it must have something to do with these printed parts.

 

Yes printed parts act totally differently than forged or cast parts. The people who make the machine will argue otherwise and people are launching parts into space that are 3D printed, but they do act different and need to be treated differently has been my experience. I am seeing more consistent material in something like Inconel verses a forging or a casting. Makes a better chip and easier to control things, but in other materials I have seen the exact opposite.

[BCW]

I don't think you will be successful on this old Hass

IMO you should move the job to a tighter machine

 

PBS should pickup this series about machine shops... This old Haas