GUAGE DESIGN FOR COMPOSITE POSITION CONTROL
GUAGE DESIGN FOR COMPOSITE POSITION CONTROL
(OP)
Hi All,
I have question on designing a hard gauage to check the composite position called out for a 4 pattern of hole. Please see the attached drawing. For the part drawing dimensioned in left upper corner, I have designed a guage to check the PLTZF and FRTZF.
My question is if I include datum A in the lower frame of the Composite position control how the design of the hard guage will change ? (CASE 2)
If I include the datum A and B in the lower frame of the composite control how the guage design will change? (CASE 3)
If you see the present guage drawing for FRTZF (without any datums in the lower frame of composite position)the gauge pins are perpendicular to the bottom surface and as group the gauge pins are oriented to side faces (datum B and datum C).
Can any one please explain me how the hard guage will change for these two requirements. Please refer to the left bottom corner of the drawing. Really confused.
I have question on designing a hard gauage to check the composite position called out for a 4 pattern of hole. Please see the attached drawing. For the part drawing dimensioned in left upper corner, I have designed a guage to check the PLTZF and FRTZF.
My question is if I include datum A in the lower frame of the Composite position control how the design of the hard guage will change ? (CASE 2)
If I include the datum A and B in the lower frame of the composite control how the guage design will change? (CASE 3)
If you see the present guage drawing for FRTZF (without any datums in the lower frame of composite position)the gauge pins are perpendicular to the bottom surface and as group the gauge pins are oriented to side faces (datum B and datum C).
Can any one please explain me how the hard guage will change for these two requirements. Please refer to the left bottom corner of the drawing. Really confused.





RE: GUAGE DESIGN FOR COMPOSITE POSITION CONTROL
2.If A and B are in lower segment pattern perpendicularity to A plus pattern parallelism to B are refined. Without B pattern could rotate clockwise or counterclockwise within upper segment tolerance zone.
RE: GUAGE DESIGN FOR COMPOSITE POSITION CONTROL
Frank
RE: GUAGE DESIGN FOR COMPOSITE POSITION CONTROL
On the datum A face of the checking fixture we have 4 pilot holes at true position. We have 4 pins of virtual condition size (9 mm)with a pilot pin attached to the fixture with a wire. All 4 positional pins must inserted in the 10 mm holes using the pilot holes. All positional pins must be inserted all the way into the holes and contact datum A face of the fixture for the part to meet the positional requirement.
I believe that there is an error in the FRTZF as shown in the composite feature control frame. Datum A should be referenced otherwise, it is correct that holes could be on any angle and not necessarily perpendicular to datum A.
I agree with the other comments about the composite feature control frames named case 2 & 3.
Dave D.
www.qmsi.ca
RE: GUAGE DESIGN FOR COMPOSITE POSITION CONTROL
If datums are not specified in the lower segment, the pattern (of the hole) is allowed to tilt or rotate within the confines of the upper segment, if the datums are specified in the lower segment, they limit the orientation relative to the specified datums.
As for the case 1 FRTZF gage design, there is no doubt that the gage pins are not fixed relative to the plate as Dave mentioned above, but I think the gage pins are fixed relative to Datum A on case 2 FRTZF, this is the difference between case 1 and case 2 FRTZF gage design.(please correct me if I am wrong here)
You need to pay more attentions on case 3 (references two datums A & B) FRTZF gage design, the basic dimension from datum B no longer applies, this is composite position tolerancing rules, basic dimensions that define location of the features apply to the upper segment only, the gage pins are located relative to each other by the basic dimension, but the gage pins are not fixed relative to datum B, the distance from datum B is not being controlled with the gage, so datum B plate should be designed on a movable slide base.
SeasonLee
RE: GUAGE DESIGN FOR COMPOSITE POSITION CONTROL
The comment that I made was that I felt that the design of the gauge for the PLTZF is not valid. If we place the part on this gauge, we would end up checking to see if the sides contact datum B & C rather than if the holes are in position.
Dave D.
www.qmsi.ca
RE: GUAGE DESIGN FOR COMPOSITE POSITION CONTROL
An electric outlet and the plug that goes into it serves as an example -- we certainly care about the location of the holes to each other (OK, they're not circular holes, but rather the three slots of an outlet). And there is no requirement that they be perpendicular to the face of the outlet...a plug that inserts into the outlet might not be flush with the face of the outlet. The juice can flow even it the body of the plug never touches the outlet. Thus, no datum is needed (although I suppose it would be wise to include one so that the slots aren't at a really crazy angle from the wall).
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
RE: GUAGE DESIGN FOR COMPOSITE POSITION CONTROL
If i summerise all of your points
1) If we dont use any datums in the lower frame of a composite control frame, the orientaion of the holes is not controlled. For this case we cannot design a fixed gauge since the holes can be tilted to datum A. I hope FRTZF needs to be checked with the Axis interpretation, surface interpretation is not possible here. The best fit guage pins can be inserted to all the 4 holes and the distance between the axis can be checked to see wheter it is inline with the FRTZF. This is how i understood. Please correct me if I am wrong.
2) If we use only one datum that is datum A in the FRTZF, then the gauge which I have mentioned in the drawing would be applicable since all the pins (dia 9.3) are made perpendicular to datum A. Please see the drawing in the original post.
3) If we use both the datums that is datum A and datum B in the lower frame, as SeasonLee mentioned we need to use some movable arrangement, so that the entire pattern of gauge pin moves in parallel to datum B. But I dont know how to design a movable arrangement here.
This is what i understood from the above discussion, Please can anyone correct me if I am wrong here.
RE: GUAGE DESIGN FOR COMPOSITE POSITION CONTROL
Also take a look at Fig. 7-49 of the standard. For that FRTZF, the fixed gage would simply be a single pin of 10 mm. That still considered a fixed, functional gage even though there are no datum references.
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
RE: GUAGE DESIGN FOR COMPOSITE POSITION CONTROL
I was not knowing this.
Thanks for the reply, your are correct. For the example you mentioned Fig 7-49 we can design a fixed gauge as you mentioned.
Also I need a small clarification from you, in the example fig 7-49 all the holes are coaxial, where as in this example it is rectangular pattern of holes, if the holes are oriented in differnt ways, can we still able to pass the patten of holes through the gauge ( as you mentioned we should not see whether the all the surfaces are exactly flattened out with the respective mating surfaces).
Please clarify does this holds good for the 4-rectangular pattern of holes as well?
RE: GUAGE DESIGN FOR COMPOSITE POSITION CONTROL
Your application where this FCF is applied should not have any fasteners into the holes otherwise the inside of the bolt head or nut face may not butt onto the mating surface.
Dave D.
www.qmsi.ca
RE: GUAGE DESIGN FOR COMPOSITE POSITION CONTROL
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
RE: GUAGE DESIGN FOR COMPOSITE POSITION CONTROL
You may find out a lot of movable slide design examples from ASME Y14.43-2003 (latest version is 2010) Dimensioning and Tolerancing Principles for Gages and Fixtures, please note that the movable slide is datum B I/O the 4 pattern pins.
Attached is an example of the design concept (this is not an example of composite position tolerancing).
SeasonLee
RE: GUAGE DESIGN FOR COMPOSITE POSITION CONTROL
SeasonLee
RE: GUAGE DESIGN FOR COMPOSITE POSITION CONTROL
Thanks a lot for sending the design concept.