This is in response to a question on a different thread -
Many newer DRO's (digital readouts) have a SDM (sub datum) function. This is a way to store multiple locations on a work piece relative to the ABS (absolute) position. This is very useful when making several of the same part especially if there are a lot of points to locate.
This sample is based on how mine works and may differ slightly on others. I have an Easson 3 axis with glass scales from DROPROS. There is a manual on there site with pictures. It is a downloadable pdf.
1) Locate a starting point (ie. the center of the work piece or a corner) with an edge finder or other method.
2) Zero out the ABS coordinates on the DRO.
3) Change function to SDM and go to point #1
4) Enter the X,Y, and Z coordinates for the point.
5) Increment the SDM point on the DRO. (maximum number of points on my DRO is 199)
REPEAT steps 4 and 5 until all points are entered.
6) Set the DRO to the SDM point number you want to locate and turn the screws until the display reads zero on all axis.
REPEAT step 6 to locate each point on the work piece.
To work on the next part of the same type mount the part in the vise and find the starting point while the DRO is in the ABS mode (absolute position mode). Once the starting point is located and the DRO axis are zeroed out while in ABS mode just perform step 6 for all the SDM points.
The SDM points are relative to the ABS point so the new part does not have to be loaded in the same exact location as the first. The only real requirement is to have a set starting point on the work piece that you can locate at the start of each new part. The SDM points are stored even if the DRO is turned off so the job can span several days.
As I said I love this feature when doing several parts of the same type. Only one real setup and I don't have to keep looking at the drawing for dimensions.
Many newer DRO's (digital readouts) have a SDM (sub datum) function. This is a way to store multiple locations on a work piece relative to the ABS (absolute) position. This is very useful when making several of the same part especially if there are a lot of points to locate.
This sample is based on how mine works and may differ slightly on others. I have an Easson 3 axis with glass scales from DROPROS. There is a manual on there site with pictures. It is a downloadable pdf.
1) Locate a starting point (ie. the center of the work piece or a corner) with an edge finder or other method.
2) Zero out the ABS coordinates on the DRO.
3) Change function to SDM and go to point #1
4) Enter the X,Y, and Z coordinates for the point.
5) Increment the SDM point on the DRO. (maximum number of points on my DRO is 199)
REPEAT steps 4 and 5 until all points are entered.
6) Set the DRO to the SDM point number you want to locate and turn the screws until the display reads zero on all axis.
REPEAT step 6 to locate each point on the work piece.
To work on the next part of the same type mount the part in the vise and find the starting point while the DRO is in the ABS mode (absolute position mode). Once the starting point is located and the DRO axis are zeroed out while in ABS mode just perform step 6 for all the SDM points.
The SDM points are relative to the ABS point so the new part does not have to be loaded in the same exact location as the first. The only real requirement is to have a set starting point on the work piece that you can locate at the start of each new part. The SDM points are stored even if the DRO is turned off so the job can span several days.
As I said I love this feature when doing several parts of the same type. Only one real setup and I don't have to keep looking at the drawing for dimensions.
