几何尺寸与公差论坛------致力于产品几何量公差标准GD&T (GDT:ASME)|New GPS(ISO)研究/CAD设计/CAM加工/CMM测量 - 查看单个帖子 - Which distance is better, point to point distance or point to line ?pl explain why?

Pate Denney • Well... If your coordinate system is set up correctly you can can use point to point ... With that being said the blueprint should probably calling it out like that, which 99%dont. I use point to point for thickness' (spar wall thickness) in camio or modus. A point to line is different the line must be bound and remember the output will vary, depending on the length and position of line. It's all about the drawing though.
1 month ago • Unlike • Like • Reply privately• Flag as inappropriate • Flag as promotion0 .
WilliamUnfollow Follow William
William Morrison • I use Geopak so am not qualified to comment on any other software. I would think thought that on depending on the required tolerance this may affect your decision. If you pick a line that is irregular or not straight you may not get as true an answer as 2 local points. I guess the best advice is to determine how you would measure it by a more conventional method and try and replicate that condition on the CMM. Hope that helps. Cheers, Willy
1 month ago • Unlike • Like • Reply privately• Flag as inappropriate • Flag as promotion0 .
AllanUnfollow Follow Allan
Allan Dulaney • Some softwares will allow you to choose along which axis for the distance, but yes, you should get a straight line distance either way, pt to pt or pt to line, unless you specify otherwise. If possible, it never hurts to verify with conventional means, calipers, height gauge, etc. Measure both ways on the CMM, then compare data with conventional readings. Where I programmed, no one believed the CMM (only when something was out of tolerance), so I always had to prove it by conventional means.
1 month ago • Unlike • Like • Reply privately• Flag as inappropriate • Flag as promotion0 .
NelsonUnfollow Follow Nelson
Nelson Rigon • If you have a plane pt2pl will be better. Try do tests on a gage block.
1 month ago • Unlike • Like • Reply privately• Flag as inappropriate • Flag as promotion1 .
JaisonUnfollow Follow Jaison
Jaison Samuel • Line to Line will give you a single value which will take a series of points and give the average value. If you need to give an official report it's better to take this method.
In other case like a tool correction we should go for point to point dimension so that we could know is there ia any deviation in the particular area.

2012-11-19, 08:29 AM	#3
huangyhg 超级版主注册日期: 04-03 帖子: 18592 精华: 36 现金: 249466 标准币资产: 1080358888 标准币	回复: Which distance is better, point to point distance or point to line ?pl explain why? Pate Denney • Well... If your coordinate system is set up correctly you can can use point to point ... With that being said the blueprint should probably calling it out like that, which 99%dont. I use point to point for thickness' (spar wall thickness) in camio or modus. A point to line is different the line must be bound and remember the output will vary, depending on the length and position of line. It's all about the drawing though. 1 month ago • Unlike • Like • Reply privately• Flag as inappropriate • Flag as promotion0 . WilliamUnfollow Follow William William Morrison • I use Geopak so am not qualified to comment on any other software. I would think thought that on depending on the required tolerance this may affect your decision. If you pick a line that is irregular or not straight you may not get as true an answer as 2 local points. I guess the best advice is to determine how you would measure it by a more conventional method and try and replicate that condition on the CMM. Hope that helps. Cheers, Willy 1 month ago • Unlike • Like • Reply privately• Flag as inappropriate • Flag as promotion0 . AllanUnfollow Follow Allan Allan Dulaney • Some softwares will allow you to choose along which axis for the distance, but yes, you should get a straight line distance either way, pt to pt or pt to line, unless you specify otherwise. If possible, it never hurts to verify with conventional means, calipers, height gauge, etc. Measure both ways on the CMM, then compare data with conventional readings. Where I programmed, no one believed the CMM (only when something was out of tolerance), so I always had to prove it by conventional means. 1 month ago • Unlike • Like • Reply privately• Flag as inappropriate • Flag as promotion0 . NelsonUnfollow Follow Nelson Nelson Rigon • If you have a plane pt2pl will be better. Try do tests on a gage block. 1 month ago • Unlike • Like • Reply privately• Flag as inappropriate • Flag as promotion1 . JaisonUnfollow Follow Jaison Jaison Samuel • Line to Line will give you a single value which will take a series of points and give the average value. If you need to give an official report it's better to take this method. In other case like a tool correction we should go for point to point dimension so that we could know is there ia any deviation in the particular area. __________________ 借用达朗贝尔的名言：前进吧，你会得到信心! [url="http://www.dimcax.com"]几何尺寸与公差标准[/url]