09/17/2007

Machine Guarding eTool Features New Thermoforming Module

Employers and employees in the plastics manufacturing industry stand to benefit
from the launch of a new Thermoforming Module for the Plastics Machinery
portion of an US-American OSHA's interactive, Web-based Machine Guarding eTool.
The module and eTool are products of the agency's alliance with the Society of
the Plastics Industry. The module identifies potential hazards and possible
solutions to reduce injuries from thermoforming, a manufacturing process using
a thermoplastic sheet or film that is fed into an oven and then heated, formed
and trimmed.

Thermoforming is a manufacturing process using thermoplastic sheet or film.
Employees load the roll of plastic sheet or film on the roll-fed thermoformer
roll stand and then thread it through the end feed rollers. When the machine is
activated, the plastic sheet or film is advanced into the oven for heating and
then into the form station where the parts are formed and then advanced to the
trim station.

In general, once the equipment is up and running in the automatic mode there is
little employee involvement, other than starting new rolls (roll fed
thermoforming), inspecting product, packaging and removing scrap materials,
unless or until something goes wrong with the equipment or process that
requires employees to take corrective action. During the forming and trimming
production process, employees are not exposed to the hazardous areas of the
machinery unless they reach into/over these guarded areas. Once the parts are
formed and trimmed, they advance to the stacker that pushes the parts upward
through the plastic web. The employee visually checks the parts for defects and
packs them into cartons for shipment.

The plastic web is then automatically wound on the scrap rewinder or it can be
trimmed and fed into a tub, conveyor, or directly in to a grinder. If the scrap
is not fed directly into a grinder, it is typically baled and then manually fed
into a web grinder/granulator.

Thermoforming equipment varies in complexity, size and cost from manufacturer
to manufacturer, and ranges from simple inexpensive semi automated machines to
highly automated systems. There are two types of thermoforming referred to in
this module:

In-Line Thermoforming where a sheet of plastic is  fed from an extruder to an
oven by use of a guide rail and pin system. (Hazards that may be associated
with the extrusion process are not addressed in this module.)


 
Roll-Fed Thermoforming where a sheet of plastic is fed from a roll into the
oven.

The e-tool illustrates the areas where potential hazards may be found and
possible solutions may be implemented when using thermoforming machines.

More info


AplusA-online.de - Source: U.S. Department of Labor  Occupational Safety & Health Administration