Tooling Tips: To Digitize or not to Digitize that is the Question
The use of laser technology in the precision metal cutting industry has begun to establish a place of its own with varied applications limited only by the manufacturer's and end user's imaginations.On...
September 1, 2002 by Mark Benoit
The use of laser technology in the precision metal cutting industry has begun to establish a place of its own with varied applications limited only by the manufacturer’s and end user’s imaginations.
One of the highlights of my career was the opportunity to apply the technologies of laser digitizing to the fabrication of mold cavities. I will share with you examples of two specific case studies where laser digitizing provided the competitive advantage.
What is laser digitizing? Laser digitizing is a three-dimensional process in which a laser beam is used to take measurements of a part, model, master, mold, die, etc. to generate a database of geometric surface information. One advantage of using a laser over a touch-probe CMM is that laser can be adjusted to a single point or several inches wide. Also, a laser does come into any direct contact with the object being scanned, thus eliminating the possibility of distortion.
Simply put, it is a type of duplicating process that allows greater accuracy, flexibility to scan parts of complex shapes; in the process facilitate reverse engineering, transfer of information to a CAD/CAM system, and product intelligence. The more fine or complex the detail on the object being scanned, the greater the value of the process.
Let’s explore two case studies to help us understand the application of this technology.
Royal Military College medallions
The requirement was to produce a medallion for the Royal Military College in Kingston ON. On the front of the medallion was the RMC crest, coat of arms, “Truth-Duty-Valour” and “RMC” (see photo). With only this military cap badge to work from I immediately saw the value of laser digitizing technology to capture the surface detail. I prepared the cap badge setup and digitized the part. Once captured digitally I could then scale and expand, compensate for overburn, cutter diameter and shrink. The final set was to cut an electrode and make the cavity in the die using EDM. Because of the fine detail I had to redress the electrode three times.
Action figure “Ripclaw”
The requirement was to produce a mold. In this case I was provided with a hand sculpted wax model. To further complicate the project, the customer was not happy with the wax model. I set about scanning only the areas of the model that the customer identified and then began meshing those digitized sections together to create the whole figure. The wax was so soft that even a change in room temperature would result in changes to the model when handled. The database was scaled, mirrored, translated, inverted, and compensated for shrink and tool diameter. In this case I cut the cavity direct.
How does the process work? The process has three main steps. The first step begins with the model preparation stage and registration of the data. The second step is the data processing. The third step is the creation of tool paths and the milling of the model, die, electrode, part, or mold.
In all cases I found that laser digitizing reduced lead-time, and created unattended man-hours. Once the part database is generated and processed for tool path creation, apprentices can often be assigned to support the project, saving on the cost of labor and improving the efficiency of your shop.
|Action figure||Make model||155||Laser digitize||65 hours|
|manual deckel /||hours||CNC machine||(40 hours|
|duplicate to||Minimal bench work||unattended)|
|cut cavity /|
|RMC medallion||Make model||170||Laser digitize||25 hours|
|manual deckel /||hours||Cut electrodes||(15 hours|
|duplicate||with CNC machine||unattended)|
|EDM||Minimal bench time|