QUALITY: BEST PRACTICE in a Fabrication Environment
by Naddir M Patel
(Calgary, Alberta, Canada)
The terms "LEAN" and "Six Sigma", although well understood and successfully leveraged in a number of industries, are a long way from acceptance in the welding/fabrication industry.
This note is therefore aimed at dispelling doubts about this sometimes much maligned and user friendly force multiplier in productivity.
Three essential parameters determine the success of an industrial operation:
Price, On-time-Delivery and Product Quality.
Quality Assurance protocols which ties in all three, thus form the Lynchpin of productivity and in-effect profitability of the operation.
The following is therefore a hypothetical Murphy's Law syndrome experienced by many fabricators, and a methodology of avoiding the resultant costly pitfalls.
The GOAL: To produce what the customers want, when they want it, exceeding their quality expectations, while being productive, profitable and safe.
- Poor scheduling and purchase of raw material and consumables. Materials being ordered piecemeal and being received at various stages of production leading to loss of productivity and man-hours.
- Poor traceability of material and manpower in the shop. Items being received without MTR (Material Test Report), material not being adequately checked against the received paperwork. Materials earmarked for one project, diverted to another, without documentation. Inadvertent material grade substitution. Non stamping by welders.
- Lack of transparency and accountability in shop operations. Issuing of drawings to the shop floor and scheduling production while being aware that revisions are in the pipeline. Welders/Fitters not being educated to ensure
(a) beginning work only after receipt of latest drawing revision,
(b) awareness of welding procedures specifications (WPS), client and/or code (pre-heat, inter-pass temperatures, test plate, etc) requirements,
(c) stamping of identifying marks and re-stamping those heat numbers that have been erased during processing.
- Issue of a plethora of NCR's (Non conformance Reports).
- Cost over-runs through extensive waste from rejection, re-work and overtime.
- Client and 3rd party inspector dis-satisfaction with quality and late delivery.
- Stratifying the ordered material, project/package wise. Streamlining inventory management by reducing or eliminating purchase of "stock" items.
- Identifying and documenting each component and MTR (Material Test Report)(at receiving) per Code and Package number. Scanning each MTR and connecting it (intranet) with individual parameters (Job #; PO (Purchase Order) #; Heat #; Plate/Tracking #). Designating a specific area/(s) for their storage, in proximity to the area of their planned welding-assembly.
- QC (Quality Control) involvement: Initiating Fabrication only after sign-on by QC and confirmed identification of the materials in the travel sheet. Substitution of material only after confirmation from QC.
- Intelligent (Lean) Operational Layout: Welders need to remain in the welding area and focus on welding. Welding operators need to be provided with specific work instructions, based on the WPS and drawing. They should not waste time in chasing drawings, weld procedures, parts or consumables. These activities need to be the responsibility of non skilled workers ("water spider") whose job function and focus is solely on maintaining material flow between work areas so that welders, fabricators and assemblers focus on their expertise and maintain their Takt time (defined as the maximum time per unit allowed to produce a product in order to meet demand). Each welding/fabrication/assembly station must operate on a cart system. The welder/fitter is provided with the specific components, consumables and tools for the part/machine he or she is working on, as well as, that for the next one. When a cart is emptied, that signals the water spider to bring the next consecutive one, all numbered as per the production and inspection schedule. This way material traceability established at receiving is maintained through the process. Waste through the use of superior, but costly components and the subsequent time lost in item tracing and/or re-ordering is avoided. By reducing this set-up time losses, having the welders/fitters focus solely on their job function. This optimization of work area logistics could conceivably reduce man-hours by 40%.
- Intelligent Scheduling: Accurate and transparent scheduling, incorporating various production steps and their set-up times. Factoring in, late receipt of components through flexible, multi-tasking of other production packages in that time interval.
- Generating specific work instructions for each job, in clear and transparent terms, which includes a process checklist (for Hydro, for example) which is duly signed off by the welder/fitter on completion and counter signed by QC. Regular skill refresher seminars (such as "Lunch and Learn meetings"); supply of weld gauges and calculators would help in reaching a benchmarked goal.
Implementing Quality is thus NOT about scrapping defective parts, but scrapping defective operational methodologies.
It is doing the right things right, the first time, and every time. It is a value adding function; which when built into the product, far from being an expense (like the policing action required in Quality Control), becomes a powerful asset propelling the economic success of the company.
Quality Assurance addresses benchmarking and standardization of procedures; transparency of responsibilities, and in-built compliance with customer and code specifications. It is the methodology of operating effectively and efficiently to not just satisfy, but exceed customer expectations.
The focus, therefore, should be on preventing the occurrence of defects (process and material variations), instead of policing and repairing defects.
Using statistical data collection and analysis methodologies it is possible to identify efficiency and capacity problems; specifically losers known as COPQ (Cost of Poor Quality), that masked as repair, re-work, set-up time or unplanned repetitive maintenance, does not show up on balance sheets, but eats away at the profit margins.
Once identified, the focus is on the resolute elimination of any "WASTE" that interrupts or hinders efficient productivity.
This is called LEAN Production Management. The total time includes the setup, changeover, maintenance and scheduled downtime.
Lean Production Management addresses Eight Wastes endemic in Production
- Waste of waiting time. Production lead time is tied up in waiting and queuing for the next sequence in the operation, typically when the flow of material (scheduling and housekeeping of raw materials), and information (process parameters, client specifications, traceability documentation etc) availability is poor. An example would be the time lost by last minute shifting of manpower from one project to another due to unavailability of raw materials.
- Waste of workforce motion. Time lost in searching for materials and tools, out of immediate reach of the work station, as well as, Non productive/non value adding operations such as re-work and defect repair.
- Transportation waste. Improper or unnecessary handling. The number of material handling operations is directly proportional to the likelihood of damage to the vessel or piping spool.
- Inventory waste. Poor scheduling, holding or purchasing excessive materials, lack of housekeeping or well defined material layout.
- Processing waste. Producing scrap and/or parts (either because of lack of traceability or lack of definitive work instructions) that require rework and repair.
- Waste from product defect. This waste goes beyond the items rejected by quality control before shipment, but actually produces a domino effect throughout the entire manufacturing process. Waiting time is increased in subsequent processes, increasing costs and lead times. Rework and re-testing may be required to make the part usable (code acceptable), increasing labor costs. Additional labor may be required for disassembly and reassembly, sorting the defective from acceptable parts. Additional materials may be needed for replacement parts. As such there is a cost escalation in both materials and manpower.
- Waste from overproduction. Poor planning leading to producing well over customer requirements, where the customer is also the next consecutive process. More raw materials are consumed and wages paid than necessary or planned, resulting in procurement of extra inventory, additional material handling and reduction in storage space and restricted work space.
- Ignoring Innovation. Not encouraging active participation amongst shop floor workers and supervisors to be innovative/creative in their respective functions.
Identifying and eliminating wasteful processes is, therefore, the Best practice that, when implemented, increases the workflow and production capacity without an increase in capital or operational costs. This LEAN methodology of continuous improvement, accelerates product delivery, combats budget overruns and perpetual over time and delivers a quality product appreciated by customers. The end result is improved cost competitiveness and business profitability.