Surface Finish Help (not waterblock related)

RalphW · 11-06-2005, 07:30 PM

Hopefully someone knowlegeable in machining can help me with this non-watercooling issue.
The part drawing specifies an average grinding finish of 1.6 microns and a maximum variance of 6.3 microns.
The actual part seems to have a pitted surface and seems quite rough.

Any idea if the part looks like it matches the drawing spec.?

BillA · 11-06-2005, 07:50 PM

who knows what average means w/o limits ?
Steve at PolarFlo is expert in such

RalphW · 11-06-2005, 11:21 PM

Quote:

Originally Posted by unregistered

who knows what average means w/o limits ?
Steve at PolarFlo is expert in such

The way it was worded to me was:

the average is 1.6um
and distance between Max and Min. is 6.3um

Don't know if that's going to make any difference since it's hard to judge by the photo.

bobo5195 · 11-07-2005, 05:14 AM

im guessing that its average roughness is 1.6 um.

Variance describes the height difference along the surface as im guessing that this is for some kind of piping. Ie lowest point is 6.3um below top point with everything all square. This to stop pipe misalignment im guessing.

zoson · 11-07-2005, 06:26 AM

Quote:

Originally Posted by RalphW

Hopefully someone knowlegeable in machining can help me with this non-watercooling issue.
The part drawing specifies an average grinding finish of 1.6 microns and a maximum variance of 6.3 microns.
The actual part seems to have a pitted surface and seems quite rough.

Any idea if the part looks like it matches the drawing spec.?

Can you just use a gasket?

billbartuska · 11-07-2005, 07:10 AM

Quote:

Originally Posted by RalphW

Hopefully someone knowlegeable in machining can help me with this non-watercooling issue.
The part drawing specifies an average grinding finish of 1.6 microns and a maximum variance of 6.3 microns.
The actual part seems to have a pitted surface and seems quite rough.

Any idea if the part looks like it matches the drawing spec.?

I'm confused. Did you make the part or was it supplied as a sample?

RalphW · 11-07-2005, 07:25 AM

I'm in the middle between the part manufacturer and the end user.
The end user won't accept the part because of the surface condition.
I'm trying to determine if the part meets it's design spec. The part maker says it does.

bobo5195 · 11-07-2005, 07:54 AM

In which case probably best to get an ISO or some kinda book out on drawing specs and make sure everything is spot on.

deeppow · 11-17-2005, 09:16 PM

I'll depart from my normally hidden mode.

Surface roughness is a fractal characteristic --- what the heck does that mean?!

It means the measurement is dependent on the tool (typically stylus size) used to measure the average.

The specification should state the measurement and the tool used in the measurement of the average quoted. Otherwise the average and variance are not unique. The requestor has given you a specification that will depend on what measurement tool you use and there a several answers.

11-06-2005, 07:30 PM	#1
RalphW Cooling Neophyte Join Date: Mar 2003 Location: Canada Posts: 32	Surface Finish Help (not waterblock related) Hopefully someone knowlegeable in machining can help me with this non-watercooling issue. The part drawing specifies an average grinding finish of 1.6 microns and a maximum variance of 6.3 microns. The actual part seems to have a pitted surface and seems quite rough. Any idea if the part looks like it matches the drawing spec.? Last edited by RalphW; 11-08-2005 at 04:27 PM.

11-17-2005, 09:16 PM	#9
deeppow Cooling Neophyte Join Date: Jul 2002 Location: Los Alamos Posts: 30	I'll depart from my normally hidden mode. Surface roughness is a fractal characteristic --- what the heck does that mean?! It means the measurement is dependent on the tool (typically stylus size) used to measure the average. The specification should state the measurement and the tool used in the measurement of the average quoted. Otherwise the average and variance are not unique. The requestor has given you a specification that will depend on what measurement tool you use and there a several answers. __________________ DFI nF4 SLI-DR @266Mhz, AMD64 3700+ SD (2.4Ghz@1.58V), OCZ PC4200 (2*512Mb) 2.5-3-3-8@3V ----- SB Audigy2ZS + Klipsch Promedia 4.1, eVGA7800GT, RAID0, 2 80G SATA HDDs ----- Iwaki MD-20RLZT -> Storm -> Chiller -> Resev, PC_Power P&C Tubo-Cool 510Express/SLI in Lian-Li PC-V1200

11-06-2005, 07:50 PM	#2
BillA CoolingWorks Tech Guy Formerly "Unregistered" Join Date: Dec 2000 Location: Posts: 2,371.493,106 Posts: 4,440	who knows what average means w/o limits ? Steve at PolarFlo is expert in such

11-07-2005, 05:14 AM	#4
bobo5195 Cooling Savant Join Date: Aug 2005 Location: uk Posts: 400	im guessing that its average roughness is 1.6 um. Variance describes the height difference along the surface as im guessing that this is for some kind of piping. Ie lowest point is 6.3um below top point with everything all square. This to stop pipe misalignment im guessing.

11-07-2005, 07:25 AM	#7
RalphW Cooling Neophyte Join Date: Mar 2003 Location: Canada Posts: 32	I'm in the middle between the part manufacturer and the end user. The end user won't accept the part because of the surface condition. I'm trying to determine if the part meets it's design spec. The part maker says it does.

11-07-2005, 07:54 AM	#8
bobo5195 Cooling Savant Join Date: Aug 2005 Location: uk Posts: 400	In which case probably best to get an ISO or some kinda book out on drawing specs and make sure everything is spot on.

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