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Need to Know: An Inside View of the Mold Before Pouring

Dec. 18, 2005
A widespread problem gets a dose of ingenuity

One of the most intriguing developments featured at the recent Steel Foundry Society of America Technical and Operating Conference was not covered in the program, but in a poster presentation from the Dept. of Industrial and Manufacturing Systems at Iowa State University. Dubbed the MoldCam, the system uses a small video camera to examine mold interiors before pouring begins.

ISU associate professor. Frank Peters explained to FMT that the system was developed by several students, undergraduate Fred Schuster in particular. Once they arrived at the idea for the MoldCam, they researched commercially available devices and materials that could be used in the concept, assembled a system for about $350, and field-tested it in “about eight foundries,” according to Peters.

And how has the system been accepted by foundries? “I know of at least one foundry that has built two of them,” Peters explained. “They said they paid for the first one with the first mold they looked at. Others are very interested in what they saw, but haven’t built one yet.”

The bill of materials compiled by the team is offered by Prof. Peters to foundries that might want to assemble their own MoldCam system. The Iowa State MoldCam system consists mainly of three components: a camera/lighting unit, a display unit, and the support structure.

The camera determines the quality of image captured. Users may select cameras that capture images in black and white or in color. Color cameras are slightly bulkier because they house three filters (red, green, blue), which also require a certain minimum amount of lighting. If the lighting conditions are below that minimum, the color camera automatically switches to black and white with a decline in image quality.

Iowa State uses a black and white 1/3-in. CCD video sensor that offers a field of view of 90°. It measures 1.77x0.74x0.74 in, and its resolution is 420 “TV lines” (the measurement of resolution.) The light source illuminates the mold interior for viewing. The student team learned that while it must be bright enough to illuminate the surrounding mold, it must not be so bright as to “blind” the camera. They also learned that the ability to focus light on surfaces near and far is a desired trait. According to their research, available light source options include flashlight bulbs, halogen bulbs, and LED lights, among others.

Cameras can be purchased that include their own lighting LED source, but they are bulkier.

For the display unit, the student team found that the challenge was balancing camera size versus image quality. The cameras recommended can produce images of sufficient quality for viewing on a 15-in TV; however, even a portable TV of that size is inconvenient for easy movement on the foundry floor. The team found that a portable 7- or 8-in. DVD player is possible, but provides adequate resolution. They point out, however, that the player must have a video-in jack to be usable for this application.

The support structure determines the mobility of the system during the inspection. Rigid systems constructed using PVC pipe or a metal rod allow non-contact entry into the mold. Adding a hinge at the end controlled by a bicycle brake wire adds additional flexibility to look around comers. The Iowa State MoldCam system uses the handle of an inspection mirror for support.

In their presentation, the students reported, “We are still experimenting with flexible systems (flexible conduit or plumber’s snake) to allow access to hard-to-reach areas. One of the problems is that if the device contacts the interior of the mold it will knock loose sand grains.”

The MoldCam development project is funded as part of the E-SMAART research portfolio, which is organized by the Cast Metals Coalition.

Prof. Peters invites foundries interested in receiving the bill of materials with device recommendations to contact him by by e-mail or phone, (tel. 515-294-3855). He adds that he hopes that foundries that develop their own MoldCam systems will provide feedback about the implementation at their facilities.