A national provider of plastic injection molding services

FAQs

 

What service do you offer?

We create injection molded materials that shield
against radiation.

What is the primary material you use?

We have developed a proprietary combination of tungsten
and polymers called PolyTungsten. While this is our primary material, we have
the capacity to use other compounds where necessary.

How can you shield radiation with a polymer?

The base polymer itself does not have innate shielding capabilities. It is the fillers that are compounded into the base polymer that effectively shield against radiation.

What fillers that can be used to shield?

In addition to tungsten, we use barium sulfate, bismuth trioxide, stainless steel, and boron.

How does PolyTungsten shield against radiation compared to lead (Pb)?

At lower levels of radiation (40-120 keV), PolyTungsten shields at the same attenuation level as lead (Pb). For higher shielding requirements, wall thicknesses may need to be adjusted.

What are the similarities and differences between lead (Pb) and PolyTungsten?

PolyTungsten and lead (Pb) have the same density, allowing PolyTungsten to shield at the same level as lead (Pb).

Lead tends to be very ductile, and in certain applications it doesn’t retain its shape very well. PolyTungsten very rigid and does retain its shape during use.

Why would I want to switch to a lead replacement?

Though PolyTungsten is more expensive than lead (Pb), an economic case can be made if the secondary operations associated with lead can be eliminated. Using PolyTungsten as a replacement eliminates the use of a very toxic material.

Our PolyTungsten is less hazardous than lead, but still gives great results.

Why have I never heard of this before?

Lead is traditionally the material of choice for radiation shielding, primarily because of its low cost. Shielding polymers are relatively new and are more expensive than lead (Pb).

Lead (Pb) has been banned in Europe due to RoHS standards, and it looks like it will be banned in the United States by 2014.

As awareness grows, we bet you’ll hear a lot more about this safer method.

How expensive is your material? How does it compare to lead (Pb)?

PolyTungsten is significantly more expensive than lead (Pb), primarily due to the tungsten component. The price varies based upon the density.

What markets or industries do you serve?

We primarily serve the medical and dental equipment markets. Our parts are used in CT scanners, x-ray machines, radiation therapy, and nuclear medicine equipment.

Is your material electrically conductive?

It is marginally conductive at an E1-E2 ohms-cm. level. For comparison, copper is 1.6 E6 ohms-cm.

Is your material RoHS-Compliant?

Yes it is. This is one of the features that give PolyTungsten an advantage over lead (Pb). Lead is not RoHS-Compliant.

Do you only work with rigid materials, or do you have flexible materials as well?

We have a 70 shore D flexible material, which is a urethane base, at an 11.0 density. This base polymer can be compounded at lower filler levels to achieve lower densities, which would reduce weight and cost.

Are there other densities available?

Unlike lead (Pb), which is only available in a single density, we can custom compound to any density between 2.7 and 11.0 grams/cubic centimeter.

Does your material remain “hot” after exposure to radiation?

Our tungsten suppliers indicate that it does not remain active after exposure to radiation.

Can you prototype before full manufacturing?

Yes. We have two prototyping approaches, and we are working on a third to facilitate the need for parts prior to tool construction.

The first is the traditional method of machining a prototype part from a block of PolyTungsten. This approach enables us to supply parts in any density.

The second method is to “print” a part using the FDM Process with a 5.0 density.

We are currently developing a third approach whereby we can prototype parts in a 10.0-11.0 density.

What material will be used to make my mold? How long will it last?

Typically we recommend non-heat-treated steel as the mold material based upon the abrasive nature of the polymers. The molds are durable and long-lasting.

How do you dispose of PolyTungsten?

It can be disposed of in a standard landfill.

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