4. Pultrusion Goes Round in Circles

a ladder	драбина	fatigue strength	межа втоми
a ski pole	лижна палка	fiber	волокно
decking	настил	to dip	заглиблювати
a vat	бак	to grab	хапати
resin	смола	to cure	вулканізувати
a die	штамп, прес-форма	batch production	серійне виробництво
a spring	пружина	hollow	пустий
a beam	балка	core material	стрижень
mileage	пробіг	silicone	кремній

Until now, pultrusion has been used to make straight composite profiles that go into everything from ladders and ski poles to industrial decking and military antennas. The process looks a lot like extrusion, except it works by pulling rather than pushing. A gripper grabs the reinforcing fibers, pulls them through a vat of resin, and then through a die. The die shapes the profile while heating the resin so that it solidifies as it exits.

Pultrusion is cheap (for composites), fast, and produces a quality part – as long as it’s straight. Now, thanks to Thomas Technik+Innovation KG of Bremervörde, Germany, pultrusion can also make curved parts of almost any radius. Potential applications include lightweight spiral springs for automobiles, circular aircraft fuselage segments, arched windows, more expressive furniture, bridge beams, pipes, and storage tanks.

Composites bring advantages to the table in many applications. Take, for example, automobile suspension springs. Composites weigh significantly less than steel, and so improve gas mileage and handling. They also demonstrate excellent fatigue strength and resist corrosion. They may even have a cost advantage in shorter production runs.

The problem with conventional molds is that by the time the fiber and resin are about two-thirds through them, the materials have become too hard to bend.

The radius pultrusion process takes a different approach. Unlike conventional pultrusion, it is not a continuous pulling process. Nor does it pull the profile through a mold. Instead, the curved mold moves along the curved profile.

It works like this. After pulling fibers through the curved mold, the gripper stops and the mold moves from the gripper backwards along the fibers. As it moves, it dips the fibers in resin and heats the resin-coated fibers so that they harden. When it reaches the end of the segment, the gripper moves forward, grabs the newly hardened pultrusion, and pulls it along the planned curve. The mold then moves back to the gripper and repeats the dip-and-cure step again.

Clearly, radius pultrusion is not as fast as conventional continuous pultrusion. Yet Thomas believes the process is attractive for spirals with radii greater than 30 centimeters. It may also prove an alternative to batch production of smaller curved parts, since it is often faster and can produce hollow profiles with multiple channels without using core materials or silicone tubing.

Speech Patterns

You may keep this book	as long as you need it.	Ви можете тримати цю книгу скільки вам потрібно.
You should buy this book		Ви маєте придбати цю книгу, оскільки вона вам потрібна.

She doesn’t want to go for a walk. Nor do I.	Вона не хоче йти гуляти. І я теж (не хочу).
They have left. Nor do we intend to stay.	Вони поїхали. Ми теж не збираємось залишатись.
That’s neither here nor there.	Не доречно. Ні в тин ні в ворота.

Exercise 1. Say whether the statements are TRUE or FALSE.

1. Until now, pultrusion has been used to make curved profiles. 2. Resin and dies are used in the manufacture process of the profiles. 3. The company that proposed a new radius pultrusion technology is situated in Austria. 4. Composite materials are corrosion resistant. 5. In the radius pultrusion technology molds are stationary. 6. The fibers are heated so that they melt. 7. In the technology some steps must be repeated.

Exercise 2. Give synonyms to the following words from the text:

to look like, a die, to exit, a storage, for example, to improve, to demonstrate, excellent, to resist, to stop, since.