System measures and records tolerance deviations of thermal-protection ceramic tiles in less than 30 seconds. Accuracy of the machine is within 0.001 inch

Meunier, G. E.

English

NASA Technical Reports Server

December 1975	 B75-10322 
fl	 NASA TECH BRIEF 
Lyndon B. Johnson Space Center 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a Subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Fast Semiautomatic Dimensional Test Set and Data Logger 
The problem: 
Dimensional verification of critical parts in an 
incoming inspection program sometimes can be very 
time consuming. One such program, the inspection 
and visual verification of thermal-protection ceramic 
tiles for a particular application, requires 20 to 30 
minutes per piece to check for out-of-specification 
dimensions and to log the data for future reference. 
The solution: 
An open-loop semiautomatic system now measures 
and records tolerance deviations of each tile in less
than 30 seconds. The accuracy of the machine, shown 
in Figure 1, is ±0.001 inch (±0.002 cm). 
How it's done: 
The machine consists of an adjustable transducer 
array mounted above and on each side of a traveling 
table. As a tile passes back and forth through the 
array, it activates the transducers which register the 
measurements on a strip recorder for a permanent 
record and subsequent data verification. It also 
activates a real-time digital display for signaling 
out-of-tolerance tiles. The machine incorporates a 
.
. a 
Figure 1. Semiautomatic Dimensional Data Logger Test Set
(continued overleaf) 
This document was prepared under the sponsorship of the National
	
Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States	 information contained in this document, or warrants that such use 
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https://ntrs.nasa.gov/search.jsp?R=19750000322 2020-03-19T20:19:48+00:00Z
SS 
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Figure 2. Tile Mounted on Test Set Transducer 
specially-designed low-pressure high-volume vacuum 
chuck to secure the tile to the traveling table. 
(Commercially-available vacuum chucks are not 
usually designed for porous material such as these 
ceramic tiles.) 
The table travels on two guide rods and is powered 
by a motor-driven jackscrew. On the first pass 
through the transducer array, the top and two sides of 
the tiles are measured. As the table ends its travel, a 
cam-and-switch arrangement rotates it 900 and 
reverses motor travel. The table recycles back through 
the array to measure the other two sides and the top. 
Each of the nine transducers is individually 
adjustable; contact is made to the tile surface by nylon 
rollers (see Figure 2). Master calibration blocks, 
constructed of aluminum, adjust the array and verify 
dimensional accuracy outputs on the strip recorder 
and digital readout. Each transducer consists of a film 
potentiometer which converts linear motion to 
corresponding output voltage. The input voltage is 
controlled by a fine-trim potentiometer and is
adjusted to obtain 1 volt output per unit motion; i.e., 
0.100 inch (0.25 cm) corresponds to 10 mV dc. The 
range of each transducer is 0.450 inch 0.143 cm). 
Note: 
Requests for further information may be directed 
to:
Technology Utilization Officer 
Johnson Space Center 
Code AT3 
Houston, Texas 77058 
Reference: TSP75- 10322 
Patent status: 
NASA has decided not to apply for a patent. 
Source: G. E. Meunier of

Rockwell International Corp.

(MSC-19554) 
B75-10322
	 Category: 07 (Machinery)


Fast semiautomatic dimensional test set and data logger

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