Sicut’s manufacturing processes, originally developed by Professor Nosker at Rutgers, the State University of New Jersey and Polywood Inc, promotes quality control and consistency at each and every step, from raw material supply through the manufacturing process to final finished product shipment. By addressing and implementing accurate testing methods, controlling the quality of supplied and blended material sources, and reducing variation, consistent products are delivered every time.
Manufacturing process for all products starts by mixing materials to exacting patented specifications. Exacting specifications require important quality control procedures to be in place.
Supplied Material Controls – All of Sicut’s products are blended from a specific formulation of recycled plastic and post-industrial, fibre-filled polymer according to the Rutgers Technology. The plastic component requires specific density, melt flow, and moisture characteristics, while the fibre polymer requires evaluation for fibre content and length. Upon receipt of supplied materials, the Materials Quality team tests the raw components for these characteristics using a defined sampling frequency. Test data is recorded electronically and reviewed daily by Plant Leadership. Material that fails to meet the specifications is quarantined and returned to the supplier to prevent possible use. Qualifying material is placed into designated storage locations for blending.
Blended Material Controls – Materials are pulled from their respective storage locations and blended to meet the specific needs of the product. Blends typically consist of a low percentage of sleeper regrind, which is scrap material that is reprocessed for use. This scrap material is generated through normal processing and quality verification practices, including extruder “vent blow” and (destructive) lot acceptance testing. The regrind process is an important recycling practice in itself, which reduces waste and improves overall material usage. Blend composition is verified and moisture content is checked after each blend to validate that the proper fibre and moisture content is attained. If necessary, the composition/moisture level is adjusted to meet required specifications. Test data is recorded electronically and published daily for review by Plant Leadership.
During manufacturing we must ensure product consistency through the monitoring and control of several factors during the extrusion process. Sensors are placed in several locations throughout the extrusion process, but are most critically monitored along the manifold, which feeds the moulds. The extruder itself has several heat zones which are also automatically monitored and controlled for temperature and pressure, both of which are impacted by the speed of the screw, which is manually controlled to maintain optimum material flow.
Zone settings are documented, posted, and closely monitored by both operators and supervisors. One key input that has a critical impact on sleeper weight is pack time of the mould. For mould sets with varying lengths, these times are recorded on the Production Report, which is the most critical process control form. The Production Report separates the moulds into specific lots and indicates when to change the Lot Code on the stamp (after the sleeper is removed from the mould).
Once the sleepers have been removed from the mould and weighed they are stamped with the location, date, shift, and lot code. Sleepers that do not meet specifications are placed in a designated scrap location and reprocessed (ground-up) for use in future blends. Acceptable sleepers are then moved to cooling racks to “cure”. At the end of each shift, the Production Reports are submitted to QA for reconciliation and testing. Graphical analyses of sleeper weights are reviewed bi- weekly by the Senior Leadership Team.
Products that have finished curing are removed from cooling racks and all are inspected visually for anomalies that impact fit, form or function. Aesthetic applications are also evaluated at this time and random sample selection is performed for lot acceptance testing (LAT).
Dimensional and mechanical tests are performed on all LAT samples. Dimensional tests include length, width, height, end perpendicularity, and straightness. Variable data is collected on length, width, and height for all LAT samples and perpendicularity and straightness are visually verified on all sleepers, with suspect sleepers measured variably. All LAT samples are tested for Modulus of Elasticity (MOE) and Modulus of Rupture (MOR) equivalencies. MOR (min) tests are performed to 3000 psi and one LAT sample per shift is destructively tested to acquire MOR (max) values. The broken sleeper is also cross-sectioned within the rail seat area and the core and shell measured and photo-documented.
Sleepers that fail inspection are rejected and placed in the designated scrap area for regrinding. LAT failures result in quarantine of the entire lot and additional testing. Disposition is made pending those results.
After testing is complete, sleepers are reconciled with the Production Report, insuring that all scrap is documented and correctly quarantined. Finished goods are moved to a designated location and all testing and production documentation is submitted for review by Plant Leadership. Graphical analyses of QA Testing are reviewed bi- weekly by the Senior Leadership Team.