Define Block Pieces and Selection Rules

Define Block Pieces and Selection Rules

Nucleo/ART(Standard and Premium) blocks have some additional parameters that must be set up in Rx-Universe.  The block and blank together look as follows:

Of the above fields, the _BLKDM (physical diameter of the block), _BLKRD (radius of curvature of the inside of the block), and _BLKCEHI (height of the block piece) must be set in Rx-Universe.  The _LBLHI and RNGH values will be calculated by the blocker, based on the difference in curvature between the block piece and the front surface of the blank, and the amount of adhesive used, and sent back to Rx-Universe.  These values will then be used when communucating with other devices.

The particular block pieces that are available, with their characteristics, and rules on when to use the block, must be set up in Rx-Universe, under "Setup", "System Settings", then the "Nucleo / Art" tab.


The ART and Nucleo blocks can be set up separately.  For each block piece:

  • the "Text" column specifies the text that will be printed on the work ticket. 
  • the "radius" field is the radius curvature of the inside block piece (_BLKRD)
  • the "min r" field is the minimum radius of curvature of the blank for this block piece
  • the "max r" field is the maximum radius of curvature of the blank for this block piece
  • the BLKCEHI column is the height of the block
  • the "diameter" fields (BLKDM)
    • this is the physical diameter of a new (unused) block piece (_BLKDM). Nucleo and standard ART blocks only come in one diameter.  The Art Premuim blocks are available in 50, 55, 60, 65, 70 and 75 mm diameters.  
    • For ART blocks, the lab can select which diameters they are going to stock by clicking on the appropriate grid cell.

Allow ART Cribbing flag, when checked, will allow a block piece to be picked, even if the radius is greater than the crib value.  Normally this is only set when the lab uses standard ART blocks although Premium blcks can be cribbed, it is not done since premium blocks are more expensive to purchase. 

ART cribbing allowance this value is added to the crib amount when selecting the block diameter to use. 

To pick a block piece, the "true curve" of a blank will be converted to radius of curvature, that radius of curvature compared to the "min r" and "max r" values for each block, and the block picked that includes the radius of curvature of the blank.  In the case of ART Premium blocks, since each block radius comes in various diameters, the block selected will be based on the required cribbing.  The cribbing required will be checked against the "Diameter selection" table for ART Premium and the "Group" will be used to select the correct block diameter along with the radius when determining the block to use..

For example, if a blank has a true curve of 5.92, in 1.53 index, that blank has a radius of curvature of 89.527.  Comparing that to the "min r" and "max r" of the block list, block piece 5 will be selected.

To add a new blockpiece or crib group to a grid, right-click on the click, and select either "Add Row" or "Remove row" as appropriate.

When you remove a row in a block selection grid, the minimum radius of the previous row will be changed to match the maximum radius in the current row (to avoid gaps).  When adding a row, however, it is the user's responsibility to ensure that the block pieces are correctly described (named), and that the selection rules are correct for the blocks.  Rx-Universe WILL allow overlap and/or gaps when block pieces are being added.

Select Block Pieces by Diameter

Because ART and Nucleo blocks can be cribbed (the cribbing process actually cribs the block down, as well as the blank), and the block pieces can be re-used, a lab will quickly find itself with many block pieces of different diameters.  To re-use, the blocks can be grouped into "groups" by diameter.  The number of groups and the sizes of each group can be defined by the lab.

Selection of these blocks of different diameters is done by means of the "diameter selection" grid:

Blocks will be physically divided into these groups after use, based on how small they were cribbed for the last job run.  In the example above, we have 5 groups of blocks; the first group will contain blocks that are up to 55mm in size; the second group up to 60mm in size, etc.  Generally speaking, the lab will want to select the largest possible block (to provide maximum support for the blank), that is no larger than necessary.  Rx-Universe will select blocks from the appropriate "group" based on the crib required for the job.  In the example above, for example, a job which has a crib value of 62 would select a block from the "65" group.