Unusual Rotomolded Applications for the Medical...

Unusual Rotomolded Applications for the

Medical Industry Presented by Patrick Long

President, Formed Plastics, Inc. [email protected]

Located in Carle Place, Long Island, NY

USA

•  Founded in 1946 by Thomas J. Long

•  Started Rotational Molding in 1961

•  2012 is our 51st year of rotomolding, making us the longest continuously operating rotomolder in the world

•  ISO 9001:2008 and ASC9100C Certified

3rd Generation Family Business

Lighting: Post Top Globes, Pendant-Type Refractors, Spheres

•  Developed the first vandal-resistant plastic light globe

•  Specialize in tight-tolerance rotomolding

•  Plastic thermo/pressure forming, CNC machining and bending

•  Mold polycarbonate, PVDF, acetal, nylon

•  “Can tell which molds are yours when I walk through our shop, because they don’t look like rotomolded parts.” –comment from a

moldmaker

SDS Frame

One part in this picture is obviously

rotomolded, but would anyone guess that the metal frame

beside the tank would be a good candidate

for conversion to rotomolding?

SDS Frame •  This frame is used as a mixer in a kidney dialysis machine, mixing and distributing various bicarbonate and acid solutions

•  Previously, the acid solutions were rusting out the metal frame

•  The solution: a rotomolded polyethylene frame

SDS Frame •  Part has a 13 mm wall

•  Internal air pressure in the cooling cycle prevents warping and speeds up the cooling process

•  Finished assembly includes 46 inserts and helicoils

•  Post-molding, helicoils are installed in areas where hole-to-hole tolerances are too tight for molded-in inserts

SDS Frame •  Multiple shrink fixtures are used to control shrinkage, especially in areas where polycarbonate windows are installed

•  Extensive quality control sign-off sheets were created to make sure that all processes are performed, including alignment of flow meters and control box cabinet

MRI Housing •  This housing was fabricated

from Kydex at very high cost until Formed Plastics successfully converted the unit to rotomolding

•  Finding suitable material was very difficult; needed to pass UL94 V0 and also be paintable

•  Formed Plastics went through three materials before finding one that worked

MRI Housing •  Aerospace-grade nylon

molded well and was paintable, but did not pass UL94 V0

•  Flame-retardant nylon 11 passed UL94 V0 and was paintable, but molded part was brittle and often broke or cracked. We later learned the material had a 35% flame-retardant additive. Also expensive– 64 Euros per kilo

•  The winner: Flame-retardant PE passed UL94 V0, molded well and could be painted, though with difficulty. Flame-retardant additives cause surface porosity, which has to be filled prior to painting

Cost to paint=3x cost to produce part

MRI Housing •  To minimize surface

porosity, mold must be kept clean and cure temperatures must be carefully controlled

•  Internal air pressure used in the cooling station to:

1.  Prevent warpage

2.  Maintain structural integrity

3.  Control shrinkage, ensuring that 3 mating parts fit

•  All machining done on 5-axis CNC machine–must hold +1.0/-0.5 mm on 26 mm dimension

Waste & Water Bottle for Medical Diagnostic Equipment

•  Should be a simple rotomolded part, but tight dimensional and flatness tolerances make it difficult

•  Must hold tolerance of +/- 1 mm on 373 mm height of bottle

Waste and Water Bottle for Medical Diagnostic Equipment

•  Required tolerance on overall height could not be held as a molded dimension

•  We designed molded-in nubs that could be machined precisely to height on a 5-axis CNC machine

Waste and Water Bottle for Medical Diagnostic Equipment

Top view

Side view

•  Part is run on machine with IRT controls that help ensure precise cycle times for cooking and cooling

•  Due to strict contamination specifications, LLDPE resin is pre-bagged

Infant Incubator Housing

•  Use compounded color for color consistency and opacity

•  Both parts are formed in a single mold and separated with a simple band saw cut after demolding


•  Tight-tolerance job necessitates the use of multiple shrink fixtures

•  Must hold +2.0 mm/-0.5 mm on 225 mm height


•  All secondary operations performed on 5-axis CNC machine

Miscellaneous Rotomolded Medical Parts

Surgical Positioning Board


Medical Water Supply Bottle


Surgical Light Diffuser


Barcode Reader Cover


Biohazard Receptacle


Medical Equipment Manifolds


Waste Tank


Arm Board


Arm for Therapy Machine


Liquid Waste Bottle


Platform for Open MRI


Waste Bottle

New Materials?

Thank you for your attention!

Unusual Rotomolded Applications for the Medical...

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