Quality Assurance in Manufacturing Yields Quality Products
AXION controls and assures the manufacturing quality each and every step of the way from raw materials, to manufacturing, to the final finished product shipped to our customers around the world.
AXION’s product manufacturing team is led by our Director of Quality, Director of Manufacturing, and Director of Materials Sourcing. By addressing and implementing accurate testing methods, controlling the quality of supplied and blended material sources, and reducing variation, AXION continues to improve consistency. Not just better quality – consistently better quality. Our quality control efforts have allowed AXION to objectively demonstrate our ability to create a consistent finished product.
Quality through Material Controls
Each of our products starts by mixing materials to exacting specifications. To obtain the highest quality and consistency from our patented formulas, AXION demands the highest quality ingredients. In order to establish and maintain consistency in the incoming material streams, several controls and quality practices are in use.
Supplied Material Controls
AXION produces ECOTRAX® Composite Railroad Ties (and other products) that are blended from a specific formulation of recycled plastic and post-industrial, fiber-filled polymer. The plastic component requires specific density, melt flow, and moisture characteristics, while the fiber polymer requires evaluation for fiber content and moisture. Upon receipt of supplied materials, AXION tests the raw components for these characteristics using a sampling frequency in accordance with ANSI Z1.4-2003. Test data is recorded electronically and reviewed by Site Leadership daily. 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 tie 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 fiber and moisture content is attained. The main concern with moisture is its potential for creating excessive voids and reducing extruder throughput. If necessary, the compostion/moisture level is adjusted to meet proper specifications. Test data is recorded electronically and published daily for review by Plant Leadership.
Quality through Manufacturing Process Controls
AXION attains product consistencies 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 mold bank(s). 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.
Most of the manifold heat zones are controlled automatically, but can be adjusted to prevent or eliminate occasional hot or cold spots that could lead to improper filling or cooling. Since the extent and range of controls are potentially limitless, it is important that specified settings or ranges of settings are maintained to reduce or eliminate variation induced by constant adjustment. These settings are documented, posted, and closely monitored by both operators and supervisors. One key input that has a critical impact on tie weight is pack time of the mold. For mold 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 molds into specific lots and indicates when to change the Lot Code on the stamp (after the tie is removed from the mold).
Once the ties have “set-up”, they are removed from the mold, weighed, and stamped with the location, date, shift, and lot code. Ties that do not meet specifications are placed in a designated scrap location and reprocessed (ground-up) for use in future blends. Acceptable ties 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 Tie Weights are reviewed bi- weekly by the Senior Leadership Team.
Quality through Control of Finished Goods
Finished Goods Controls
Example: ECOTRAX® Ties that have finished curing are removed from cooling racks and are conveyed through X-Ray and embossing. X-Ray is used to determine if there are any critical voids, particularly in potential fatigue locations or areas where spikes or other hardware may be driven.
During this process, ties are also 100% 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), in accordance with ANSI Z1.4-2003.
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 ties, with suspect ties 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 psig and one LAT sample per shift is destructively tested to acquire MOR (max) values.
The broken tie is also cross-sectioned within the rail seat area and the core and shell measured and photo-documented.
Ties that fail a 100% inspection are rejected and placed in the designated scrap area for regrinding. LAT failures result in quarantine of the entire lot and additional testing is required in accordance with ANSI Z1.4-2003. Disposition is made pending those results.
After testing is complete, ties 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
About ANSI Sampling Standards
Q: What is ANSI?
A: The American National Standards Institute (ANSI) was founded in 1918. As the voice of the U.S. standards and conformity assessment system, the American National Standards Institute empowers its members and constituents to strengthen the U.S. marketplace position in the global economy while helping to assure the safety and health of consumers and the protection of the environment. AXION follows ANSI quality sampling standards to ensure consistant quality manufacturing of our products.
ANSI website >>
For Additional Information, please do not hesitate to contact AXION Structural Innovations.
EXECUTIVE LEADERSHIP TEAM