How often do you have to redo or rework someone else’s work output? Or how often are defects and problems found at the end of a process? If a defect occurs in step two, why is it not discovered until the 99th step when inspection takes place? Think of all of the costs incurred in processing the defective item from step two to step 99. What about the cost of scrap or, if it’s salvageable, the cost of repair and rework and re-inspection? Or worse yet, the effects remain undetected until they end up in customers’ hands. What about the cost of recalls, warranty claims, lawsuits, the loss of customers, and bad reputation?
Quality should be assured at the source. The principle of quality at the source means that quality is assured at the source where work is performed so that no defects are passed down to the next step or to subsequent processes.
Quality at the source can be achieved in one or more of the following ways: quality by design, quality by process monitoring and control, and quality by self-checks and verification.
Quality by design is used to ensure that it is always done right the first time. To ensure quality by design, mistake proofing, error proofing, or poka-yoke as it is called in lean are used. For example, when completing an online form, it will not allow you to proceed to the next screen if all essential fields in the current screen are not completed correctly first. By design, it is impossible to proceed with missing information. Let me share another example: charging your phone. By design, the charger plug can fit into the phone facing up or down. Both ways will fit so you don’t risk damaging the phone or charger. It is designed to avoid the tendency to shove the plug into the phone the wrong way.
Quality by processing monitoring and control where tools such as statistical process control are used to ensure that critical process parameters are monitored and controlled. For example, the control of baking time and oven temperature when baking pizzas.
Quality by self-check and verification. To assure quality at the source this way, develop and implement procedures and protocols that mandate it, and ensure compliance to those procedures. For example, airline pilots are required to perform a preflight checklist before pulling away from the gate. Another example, before a surgery, nurses identify the patient’s identify and surgical procedure, comparing verbal responses to patient records. Internally, everyone should have the responsibility and authority to pull the cord to stop defects from being produced and to bring it to the attention of supervisors or management, all without any fear of repercussions.
Management and employees must embrace this mindset, the mindset of doing it right the first time, a mindset where quality trumps production quotas, where metrics and rewards encourage good quality output and do not reward quantity over quality. Externally, at suppliers, quality at the source can be implemented the same way, by design, by process monitoring and control, and by self-checks and verification. As a customer, you can conduct audits to verify supplier performance. Not only audits on products, but also on processes to ensure that supplier processes have sufficiently good process capability to produce defect-free products. If these audits are successful, inspections at the receiving dock can be reduced or even eliminated. Just-in-time deliveries can then be made directly from the supplier to the points of use in your production line.
In summary, quality at the source facilitates just-in-time flow, being more responsive to customer demand without any hiccups or delays. It is more cost-effective to do it right the first time to prevent defects from occurring or from being passed down to subsequent steps and processes. So, the next time you have to rework or redo someone else’s work, think about quality at the source.