Surface Grinding estimate help

[cruzinrob83]

How do grinding shops quote Blanchard / mattison by grinding per square inch? How does that work. Is there some type of equation out there for it? any help would be great.

 

[unclesyd]

The cost per square inch for grinding would normally be used for repetitive process like grinding fine blanks where other cost are known.

When we do estimate in house grinding cost we use an envelope, normally a circle, that will enclose the part to be ground, not the actual square inches of surface area of the part.
There are a lot more things that involved in getting n estimated cost. The grinding wheel parameters like solid or segmented, grain size, etc. Amount of metal to be remove along with the surface finish required. What is the infeed rate of the wheel. Work holding setup and one or two sided finish. All this is added to the cost of labor and cost of running the machine. Cost of running the machine can be calculated several ways, like power required, annualized cost for the machine. return on investment, and depreciation of the machine.
One thing to remember is that you have to figure starting at the highest point above the plane of interest when grinding.

If your CAD program want give you a surface area you could use the old way of superimposing the surface on a grid for an a good estimate.

 

[cruzinrob83]

Hey thanks for replying

So what would be a general idea for quoting, like what most grind shops do to get their prices close to one another. cause not every one has the same amount of overhead as other guys, but they always seem to be in the same general price range.

 

[unclesyd]

I assume that the is a price comparison with other vendors. This data is used as starting point for the job at hand with any extras being adders.
The biggest affect on this basic cost would be the labor component as most of the other components are essentially equal.