Laboratory: A test facility that can include chemical, metallurgical, dimensional, physical, electrical and reliability testing or test validation.
Laboratory scope: A record containing the specific tests, evaluations and calibrations a laboratory has the ability and competency to perform, the list of equipment it uses, and a list of the methods and standards to which it adheres to each of these.
Last off part comparison: A comparison of the last part off a production run with a part off the next production run to verify that the quality level is equivalent.
Layout inspection: The complete measurement of all dimensions shown on a design record.
Leadership: An essential part of a quality improvement effort. Organization leaders must establish a vision, communicate that vision to those in the organization and provide the tools and knowledge necessary to accomplish the vision.
Lead time: The total time a customer must wait to receive a product after placing an order.
Lean: Producing the maximum sellable products or services at the lowest operational cost while optimizing inventory levels.
Lean enterprise: A manufacturing company organized to eliminate all unproductive effort and unnecessary investment, both on the shop floor and in office functions.
Lean manufacturing/production: An initiative focused on eliminating all waste in manufacturing processes. Principles of lean manufacturing include zero waiting time, zero inventory, scheduling (internal customer pull instead of push system), batch to flow (cut batch sizes), line balancing and cutting actual process times. The production systems are characterized by optimum automation, just-in-time supplier delivery disciplines, quick changeover times, high levels of quality and continuous improvement.
Lean migration: The journey from traditional manufacturing methods to one in which all forms of waste are systematically eliminated.
Level loading: A technique for balancing production throughput over time. Life cycle stages: Design, manufacturing, assembly, installation, operation and shutdown periods of product development
Listening post: An individual who, by virtue of his or her potential for having contact with customers, is designated to collect, document and transmit pertinent feedback to a central collection authority in the organization.
Load-load: A method of conducting single-piece flow in which the operator proceeds from machine to machine, taking the part from one machine and loading it into the next. The lines allow different parts of a production process to be completed by one operator, eliminating the need to move around large batches of work-in-progress inventory.
Lost customer analysis: Analysis conducted to determine why a customer or a class of customers was lost.
Lot: A defined quantity of product accumulated under conditions considered uniform for sampling purposes.
Lot, batch: A definite quantity of some product manufactured under conditions of production that are considered uniform.
Lot quality: The value of percentage defective or of defects per hundred units in a lot.
Lot size (also referred to as N): The number of units in a lot.
Lot tolerance percentage defective (LTPD): Expressed in percentage defective, the poorest quality in an individual lot that should be accepted. Note: LTPD is used as a basis for some inspection systems and is commonly associated with a small consumer risk.
Lower control limit (LCL): Control limit for points below the central line in a control chart.