Job Cards

Job cards – are these bureaucratic pieces of paperwork worth anything? The tracking of work, quality control indicators, dates and timing, and non-conformance can be tagged onto this tool and production control and monitoring can be greatly enhanced. The job card can be historical and diagnostic.

Can a tannery run production without a job card for each batch of work going through the facility? The answer is that it can, if an alternative is used or if the tannery system is very simple. The answer is not if the tannery is trying to keep track of what work is moving through the facility and the company process is complex.

Most modern tanneries are complex, with multiple work streams that are moving through the factory. Job cards can be simple instructions that tie the work order (received from sales) to a tracking document that allows the production team to see what stage the work is at and what inputs at various stages are needed. Complex job cards, have quality control linked and advanced inventory control to them.

Information flow
Information that simple job cards typically contain include the following (this list is not exhaustive): 

• Customer name (can be coded)
• Final target article (e.g., shoe upper)
• Specific recipe to be used
• Desired colour (if appropriate)
• Number of hides/skins/splits being processed (raw material)
• Type of raw material being processed
• Weight or area (m2, or ft2)
• Any non-conformance
• Article specifications (thickness, chromium content, grading requirements, or a customer specification)
• Delivery dates (times)
• Special packaging instructions
• Other special instructions
• Sign off (allowing the work to be progressed to the next department)

The job card normally accompanies the recipes to be used. Consider a work order for 15,000 ft² of leather coming in from the sales department. The production manager considers the work already in progress and the tannery’s current capacity. Modern tanneries use scheduling software, a wall planner, or a spreadsheet that shows equipment, the day of the week and allows the manager to understand what equipment is available and when they can fit the new work order in.

Armed with this information the manager can commit to when a work item will start and a job card (and its associated paperwork) is printed out or prepared by hand. The initial raw material is selected for the job and the weight or area is relayed to the scheduling team. The recipes for all the stages relevant to that weight or area can now be calculated. That paperwork pack can then be placed into protective dust or waterproof sheets and can accompany the raw material into process. Technicians, managers, and operators can sign off or add comments to that paperwork, allowing the quality controllers to see that all the steps are being done and the details of any deviations, variations, or anomalies can be recorded. The management team, sales team, or controllers can consult the job card to identify progress, pre-empt bottlenecks, or can shuffle work priorities (especially bottleneck machines). The major vulnerability of this type of job card is the ability for a tremendous amount of data to be lost if the job card is lost, damaged significantly, or the data is not entered (or not correctly). Clear responsibility and clear conservation habits can help keep this simple system running effectively. Large complex job cards that are filled in by hand suffer from illegible handwriting, the inability to digitally search in a database of job cards, and have a high activation energy (making lazy workers reluctant to fill them in).

Quality control
Many global tanneries now have to meet a long list of conformance and compliance requirements. Restricted substance lists, quality gates, and conformance to ISO and LWG/SLF auditing standards, means that even more data is required to be collected. Information that is often included so that traceability can be enhanced and that post sale queries can be answered have meant that the job card has become quite a complex document.
Modern information that is further required (from those above) for capture includes:

• Chemical batch numbers
• Quality key indicators (that are captured for statistical process control charts, e.g., pH)
• Technical recipe modifications (signed off by R&D or appropriate managers)
• Testing records and signatories
• Specific equipment used
• Test equipment used
• Dates of calibrations
• Who the calibrations were done by
• Hide/skin/split identifying numbers (for traceability)
• Cutting data
• Wastes generated
• Packaging special instructions
• Solvent data
• Location of emergency information
• Special safety instructions
• Safety data collection
• Other audit specific information

As audit standards and protocols change and as new compliance-type regulations trickle down into the tanneries these requirements continue to grow, taking the simple job card into quite complex areas.

Digital job cards
Enterprise resource planning (ERP) and customer management systems (CMS) are progressively becoming the tools of choice for larger tanneries. Pieces of paper, easy to lose data, or easy to “cheat” methods of recording are quickly falling out of favour when the cost of bad data increases. Advanced inventory control and time-consuming stock taking has meant that the return on investment for automated, or at the very least, digital systems, has been seriously reduced. Many tanneries have bought ERP systems that help with production control at levels never thought possible.

Production has become progressively automated with drum dosing, chemical barcodes (and scanners), and with handling robotics. A job card now has a set of QR codes that allow an operator to scan the card when instructed to do so in the process recipe control (that appears on the computer monitors). Coloured lights that warn an operator that attention is needed on the computer screens. Detailed checklists on the computer monitors allow the operator to follow in sequence the tests, chemical additions, or mechanical operations that must take place. Management sign offs keep the workers supervised and allow constant monitoring of all operations.

pH meters, weighing scale measurements, and even photography can be linked to digital capture of work in progress. When prompted, the production staff are taking snapshots of the progress of the recipe and automated software can allow the recipe to proceed, with water and chemicals being automatically dosed, or the drum rotation altered. Weighing load cells in the tanning drum axles allow the live weight of the material in the drums to be monitored and adjustments to the recipe can take place. Accelerometers will be a certain addition to the process vessels of the future - that will measure the forces in the drum while the material is moving. Digital job cards make all the analysis and tracking of this data easier.

In the next issue: Anaerobic leather - most people have heard of the leather find that was a shoe or a bag from antiquity, stored in a preservation condition that has allowed the relic to last several hundred years without being broken down. Is this the model of how, as a material, leather can be stored in a fossilised form taking carbon out of the atmosphere and putting it back into the ground? Or, will a clever tannery come along and produce a material that does well in anaerobic conditions?