flatness measurement

[Bartek]

Hi,
I have a round object, and I need to measure flatness base on dedicated two diameters on 400 points, how to program, in PC-DMIS to take a points from this dedicated diamters automatically

[Schrocknroll]

If I understand the question correctly, you need to measure a plane using points located on two basic diameters using 400 points. I don't know if you mean 400 each or 400 total, but there are two ways to do it.

The old school method would be to measure one point located half the diameter from center. Then copy and paste with pattern based on how many points you want total. If you want 400 points on that diameter use a pattern of .9 degrees 399 times. Do that for both diameters and then construct a plane from them.

PC-DMIS now has an autoplane that can use a radial pattern, but it only works for 2 diameters if the second is twice the size of the first. You define the spacer as the size of the first diameter and if you have 2 rows, it will double the spacer for the second.

[neil.challinor]

There is more flexibility if you use one of the other measurement strategies within the auto plane feature instead of the default. Choose either the adaptive plane circle scan or the TTP plane circle strategy. You should be able to set it to measure two concentric circular paths, spaced as desired. To achieve an exact number of hits you will probably have to play around with the hit density / number of points per millimetre.

[dph51]

Setting filter/distance in scan parameters.


The scans need to have the identical # of hits, so the scan filter/distance needs to be calculated for each scan.

A few assignments and calculations.

PI calculation

D1 & D2 ex. diams 50.8 and 73.015

C1 & C2 circumference for each diameter

NUM_ARCS arcs [hits] = 400

ARC_LENGTH_1 & ARC_LENGTH_2 arc length [for filter/distance in scan parameters]

ASSIGN/PI = ACOS(0)*2

ASSIGN/D1 = 50.8
ASSIGN/D2 = 73.015

ASSIGN/C1 = PI*D1
ASSIGN/C2 = PI*D2

ASSIGN/NUM_ARCS = 400

ASSIGN/ARC_LENGTH_1 = C1/NUM_ARCS
ASSIGN/ARC_LENGTH _2 = C2/NUM_ARCS

Hope this helps