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The most important current problem associated with aircraft
production is the necessity for a reduction in the time
cycle from design to completion of the first production machine.
Tool manufacture is one aspect in which improvement is desirable.
The use of thermo- and setting-plastics for drop-hammer
and double-curvature panel drill jigs is examined aver a wide
technical and economic field, in order to establish a sound
foundation for investigating the suitability of plastics for
tooling. Tools were designed to isolate the variable parameters
and a study of their behaviour has commenced , dth the assistance
of high-speed filming, to ascertain the limitations of the various
materials. Casting resins are preferable for both punches and
dies although the laminated form, in addition to being the better
type for pcnel drill jigs, appears to be the most satisfactory
die material available at present.
It was concluded that plastics facilitate easier and
cheaper tool production titan is practicable with zinc and, for
the tools produced, reduce the necessary time cycle of production
by about 80 per cent with a corresponding reduction in the man.-
hours required.
In the tests made to develop suitable plastic tools,
attention was concentrated on the development of a suitable
slightly flexible punch, and a rigid diet following the most
promising indications of this work.
It was found that Tenite Medium Bard was a good punch
material with a life of over 1,000 components, the springback
differing from that of a Kayen Alloy punch by less than one
degree for all the tool shapes tested. The economic savings
are approximately cost 87 per cent, man-hours 84 per cent, and
time cycle 81 per cent. It should. be noted that the ;lunch and
die selected for this test was a severe forming case of a double
curvature bead.
The most satisfactory die developed was manufactured
from Aralditc D resin, glass fibre and french chalk. Limited
tests with a Tenite M.H. punch gave satisfactory results for
short runs, and in all probability longer runs could be made.
The economic reductions effected were; cost, 68.5 per cent and
man-hours, 86 per cent. |
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