top of page
Writer's picturefabio65bordi

Production scrap (waste): management, reduction and recycling

Updated: Jul 4, 2022

A product is defined as scrap when its characteristics values fall outside the range of acceptability.

No one is willing to support processes whose indicators of the scrap are not constantly improving (lowering): in fact, these KPIs are precious litmus tests on the real ability of the organization to work on continuous improvement.

The definition of the acceptability range, i.e., the specifications, requires a deep knowledge of the product and the processes, as well as the potential negative effects that the characteristics have when they degrade and veer towards an out-of-specification condition. In this context it arises the ability of an organization to generate FMEA studies that in turn help to generate well-placed specifications.

Given for sure that the specifications are optimal and there is agreement on them between supplier and customer, it is a matter of directing the implementation processes towards the center of all the tolerances thus defined: all situations in which all this does not happen should require further study and redefinition of FMEA and Control Plan.

The waste impacts the company's PL (Profit & Loss) in the heaviest possible way: it takes added value away reducing the bottom line profit. It can be compared to an increase in cost of purchased materials: unfortunately in this case, we cannot "blame" anyone else but ourselves.


Scrap and Quality

A process that generates scrap jeopardizes the quality of the product: the concept of process stability must be studied (see the dedicated tool) and applied everywhere. The ideal Control Plan includes a number of key features that must be maintained in perfect stability to place production at the "minimum scrap" state. When these characteristics show values that thicken near the limits of acceptability, the quality becomes at risk. The ability in minimizing scrap depends on our skill to solve problems and prevent them; there are rivers of literature that might help to refine our aptitude in the analysis of problems and their solution. At the base of all this, however, I suggest being as creative as possible to favor situations, even showy and counter-current, which trigger and increase in all workers the culture of scrap abatement. An example that I really like is to expose it, on display, along areas of usual walk within the building; I say this because I happened to witness cases of concealment of non-compliant products or piece parts to appear mistakenly more virtuous than other colleagues or teams. Without prejudice to the good faith of colleagues, human nature tends to mask/mitigate problems, including scrap. It is therefore imperative to regularly carry out inspections (audits) to be able to trust the data: once or twice per shift depending on the situation. Being able to afford it, the automatic collection with dedicated programs is even better. In this case I would have the doubt that, by relying on a software or automatic systems that reject and segregate non-compliant parts, the determining factor of the operator's self-knowledge might be missing. The operator might overlook in real time the severity of the problem in progress and he/she could delay the beginning of the problem troubleshooting.



Reduction of scrap

It is good to set ourselves a goal that is well measurable, ambitious and achievable. A criterion can be that of reducing 50% of the final value of the previous year: the goal must be detailed by month and by department, as well as shared and embraced by all. However, it is not enough: it is shift after shift that we, always confronting ourselves with our goal, will be able to overcome it; "counting the dead" after a week is already too late. It is not for everyone to work well on reducing scrap; when I have to audit a company or choose a supplier or get an idea of a customer, I immediately go and audit how they are structured in reducing the percentage of non-conforming products: if a company excels in this discipline, it is almost guaranteed that they are reliable and competent. The organization must have at all times the exact picture of the scrap produced by each line, machine and process: every other situation inhibits the resolving PDCA discipline. The ideal is to have the scrap breakdown both quantitatively and economically: how much material did I have to throw away, and how much was it worth? What are all the scrap items, starting with the most "expensive" ones? What are the “riskiest” scrap items from a qualitative perspective? The attached tool tries to answer these questions in a simple and intuitive way. The tool also measures productivity, which is not the case.

How to use "Line_1_Scrap_MGT:

The file contains macros, so note the .xlsm extension.

1_ The scrap section develops horizontally and includes 91 fields where you can choose the 2_ scrap items that you want to keep under control.

3_ The indicated blocks (B_1, B_2 ...) can be modified at will.

4_ The sheets have and must have identical architecture.

5_ Data entry is usually manual.

6_ Each shift has a dedicated sheet.

7_ It is possible to extract the data in the window between any two dates.

By equipping yourself with a sufficiently large screen you can have a glance of the most critical processes. Depending on the threshold colors chosen in the conditional format, the visual impact can be more or less immediate: here it is orange between 10 and 20 and red over 21. The input of the cost of the components is slightly more protected and structured and requires knowledge of the mounting flow.

The cost of the part that is rejected is hidden by the top graph: by shifting it, the blue cells containing the costs are exposed and can be changed.

In the example, the cost of the B_1_3 component (0.024) is the sum of the component B_1_1 and B_1_2 plus 0.0141. By having the cost list and the assembly flow, it is possible to achieve a very high level of detail in the cost of discarded materials.


The cost of the details must be updated at least on an annual basis: better if semestrally .


Scrap recycling

I will not dwell on the importance of recycling to reuse scrap materials. It seems important to me to reflect instead on the quality of the scrap that you intend to resell, making a distinction between "clean" and "dirty" (or mixed) scrap. The activities that aim to divide the types of scrap are aimed at valorize its density as much as possible. It is necessary to make a break-even analysis between the internal cost necessary to clean up the scrap and the best price in the resale of separate materials. Most of the time, surprisingly, we will see that cleaning the waste, even partially, brings unexpected advantages. It goes without saying that scrap must be minimized regardless of how well we manage to place it in the recycling market.







15 views0 comments

Recent Posts

See All

Comments


bottom of page