MultiVision is a high resolution digital registration system that uses media registration marks. These media registration marks are also known as fiducials and are printed on the material as ¼ inch black dots around each segment that is to be cut. This is done by simply adding them to your original design file. The high resolution digital camera then recognizes the marks and the information is processed by the software. The MultiVision software compares the fiducials to those on the original file and readjusts the toolpath to compensate for any discrepancies. There are various features of the MultiVision system that assist with this process and are found in the MultiVision Advanced Menu. These items include Fast Find, Auto Focus, Manual and Auto Find Setting, Correlation, Retake Distance, Job Console Auto Option, Home on Material, and Flip to Cut. The following will explore two of the mentioned items; Correlation and Home on Material:
In the context of the MultiVision system correlation signifies how well it is able to acquire the fiducial that it is directed to find. It is essentially a number between 0.001 and 1.000 inches that denotes the relationship between that element on the original file and the same item on the material being cut. In this case it is denoting the relationship between the original fiducial and the print fiducial. The correlation value takes into account the:
- shape of the fiducial on the print
- size of the fiducial on the print compared to the size in the file
- X and Y location in the file compared to the actual one on the print
- contrast between the fiducial and the background
For digital cutting a good correlation value is one that is within the range from one thousandths to fifty-thousandths of an inch. You can find the correlation value at the bottom of the keypad display. If the correlation is greater than the one indicated then the machine will stop and ask you to find the fiducial again. To change or modify the correlation settings go to Menu à Vision à Correlation and you will see on the screen that you can change the value entered. If you increase the correlation value then the MultiVision system will allow prints with a lower quality to be registered. However if the correlation is too high and is registering low quality prints, then errors can occur and your cut quality will suffer.
Home on Material
This menu item is useful if you find that you are cutting many different prints in one day. High volume production may involve prints that vary significantly from one another and do not have the fiducials in the same place. This would then require a great amount of resetting the home position each time a different piece is being cut. Regularly the job console automatically chooses the closest fiducial to the X0 Y0 edge to be the first one registered. However this first fiducial can vary based on how the piece is placed down on the cutting table due to rotation, or misalignment. This would cause incorrect registration and an error in the cut. Therefore the Home on Material item on the advanced menu provides a efficient solution to save you time and ensure that you are not needlessly resetting your home position. The first step is to set up a jig, or pop-up pins to mark where your home position will be. This will become the (0,0) point for all your production runs. The corner of the material will fit right into the corner of the jig, making sure that is the starting place for whatever is being cut. The next step is to go into the job console and make the change. Go to ToolsàVisionàVision Modeà Check box soft home not set near first fiducial. This will allow the digital registration system to run from the corner of the material, and find the closest fiducial to that location instead of searching for the one closest to the edge.