Manual vs DCC alignment

Thank you bigtall! I do see that I forgot to translate Z in my A4 alignment. Ugh, I'm starting to think it's more difficult to edit someone else's programs than to create your own. I will change that now and see if it has an effect on my issue. And, as requested, here is the code for the creation of datum D and the TP dimension code.

DAT_D_CYL  =FEAT/CYLINDER,RECT,IN,MAX_INSC
            THEO/6.141,-0.008,-0.02,-1,-0.0000985,-0.0002292,124.435,7.75
            ACTL/6.138,0.006,0.003,-1,0.000159,0.0002539,124.425,7.81
            CONSTR/CYLINDER,BF,D_BOT,D_MID,D_TOP,,
DIM LOC16= TRUE POSITION OF CYLINDER DAT_D_CYL  USE AXIS=START PT  REF LENGTH=0.000  UNITS=MM ,$
GRAPH=OFF  TEXT=OFF  MULT=10.00  OUTPUT=BOTH  DEV PERPEN CENTERLINE=OFF  DISPLAY=DIAMETER
AX    MEAS      NOMINAL     +TOL       -TOL       BONUS       DEV      OUTTOL   
Y       0.004      0.000                                       0.004           
Z       0.012      0.000                                       0.012           
DF                            0.025      0.025                -0.010      0.000 --#------
TP                   RFS      0.040                 0.000      0.026      0.000 -----#---
END OF DIMENSION LOC16

Unfortunately we didn't cover any of these topics in class. I'm not familiar with read points, although I've seen them mentioned several times in this forum. We do have threaded gridplates. Currently cmm 2 is mainly used for checking the part with the fixture that my original question involved. Occasionally we check service parts there which do not have fixtures, so I usually set them up the best I can with the fixturing tool set we have from Te-co and run a manual alignment. Cmm 3 is currently being used primarily to measure a new part we are running, and that fixture rarely moves. We are in the process of having a threaded gridplate built for that machine (which I'm thoroughly excited about ). I have noticed better position outputs on machine 2 after adding the second dcc alignment. I used to talk about being able to hear the positional difference from part to part when an ID was measured, but apparently I was the only one who noticed. I no longer hear such a huge difference. I'm also unfamiliar with iterative alignments, although I've seen them mentioned here as well. This has brought to mind one more small question while I'm here. On cmm 3 (PCDMIS 2014.1) it seems like I remember the probe retracting automatically when a manual point was taken. It no longer does this. Now you have to manually back the probe away from the part. We've done a lot of digging into the settings, although I really didn't change any, and I wonder if this may be due to a box accidentally being unchecked. Any ideas?

And thanks for the fix Josh. It's a blessing and a curse. Which one just depends on which day I'm asked .

We run higher volume automotive parts in many of the machines and if you're lucky and have rayco, or threaded gridplates, you can do what I call drop an go programs.

"Find" the part using your check distance set to 4" or 100mm, then do a rough DCC alignment (fixture to part), then a refined alignment 2nd DCC on part, and go from there.

Operators just have to set up fixtures per instructions (and pictures) in program and press execute - NO moving of the probe head manually AT all!

Works awesome to keep the cave monkey's from wrecking TP20's. Went from 22K last year in TP20's to 2K this year to date. Plus it speeds up the number of parts you can check a shift when you're not needing to take all the time to manually align parts.

Also, when you do the 2 DCC alignments you'll find that on especially tight positional tolerance parts (say .030mm) you'll usually gain a few microns when doing this and those extra microns make the difference between scrapping good parts!

My .02 cents

4/1/96

Just a general note. I have never used manual alignments in 15+ years of programming.

My suggestion is avoid the manual alignment. There is no good reason for the DCC alignment to give you poorer results. If this is the case then as stated above there is a difference in the alignments, or probe points. A DCC probing should always give you better results.

I suggest using a READPOINT, and letting the machine do the rest. Inserting a pic of the probe at the start position, or readpoint, into your operator comment is easy and very helpful. I have just stepped into a situation where manual alignments with no pics, and then dcc alignments based from MCS are used in most, if not all the programs, and it is nothing short of a mess.

I understand you may not be in a position to change the way programs are started, but if you can get that change made you'll be glad you did.