When Part Gauging is a Bottleneck

 Defined processes are critical to continuous improvement in manufacturing. Key measurement points are identified and metrics are put in place to measure processes. The resulting data is meant to be used for process improvement. It is in the evaluation of the data that bottlenecks can be discovered. In manufacturing, manual gauging is often responsible for bottlenecks.

Bottlenecks in manufacturing can be caused by labor shortages, which force employees to split time between processes. The resulting throughput irregularities negatively impact downstream processes. Technology can also cause bottlenecks if it is antiquated and slow, or improperly selected for the desired purpose.

In manufacturing, manual gauging is one of the processes that is often responsible for bottlenecks. Whether performed in-process or at incoming inspection, it is a slow but necessary task. Additionally, Coordinate Measuring Machines (CMMs) or other specialty inspection systems in the Quality Control lab are often identified as significant process bottlenecks.

Here’s how automating manual gauging can reduce or even eliminate these bottlenecks.

In-Process Manual Gauging

A machine operator’s priority is to keep the machine running, producing parts that fall within specified tolerances. In addition to loading and unloading the machine, the operator is often tasked with gauging, per an inspection report, to ensure the parts are acceptable. Upon completion of a cycle, they may be required to make several manual measurements using instruments such as calipers, micrometers, and thread gauges.

If the gauging process is longer than the machine cycle, then the machine will sit idle for a period after each cycle. In this case the inspection process is the bottleneck, and the cost is idle spindle time. That idle spindle time over 1, 2, or 3 shifts adds up quickly and precludes optimal machine output.

An operator under pressure to keep production steady may inadvertently neglect the manual gauging process. There are multiple costs associated with this. Improperly measured parts, or parts not measured at all, do not yield the data required to make ideal machine adjustments. The result could be production of parts that fall outside of acceptable tolerances.

Parts found to be unacceptable at a downstream manufacturing process could be scrapped or require re-work. Both are costly. If not caught in a downstream process, bad parts could cause a damaged customer relationship or worse. Think implantable medical devices or aerospace components.

Adding an automated gauging system to the process could eliminate these risks.

Incoming Inspection

Outsourcing parts production by manufacturers is very common. There are shops that specialize in different types of parts production. For example, a swiss machine shop can offer high mix/low volume and high volume/low mix production of parts from standard bar stock. Consequently, a manufacturer with the need for a part suited for a swiss machine will outsource the work because they do not have the capability or the capacity themselves.

The manufacturer that has hired the swiss shop to produce those parts will require some level of inspection by the swiss shop to avoid buying non-conforming parts. When these parts are critical, the manufacturer may choose to perform incoming inspection upon receipt of the parts to ensure conformance.

In some shops, the delivery of these types of parts is not so frequent as to warrant a dedicated, full-time inspector. Incoming parts will sit in a staging area until they can be inspected. The inspector is likely an employee with primary responsibilities elsewhere in the organization. When they are taken away from their regular role, that process is temporarily put on hold and a bottleneck can result there.

Incoming parts awaiting inspection can slow or stop downstream processes where they are needed, creating an additional bottleneck.

An automated gauging system designed for the inspection of incoming parts can relieve both of these bottlenecks. As an additional benefit of automation, in some instances, the manufacturer could choose to do 100% inspection on incoming parts and only pay for those within acceptable tolerance.

At the CMM

Most manufacturing facilities have a Quality Control lab that contains more accurate, specialized measuring systems. Systems like CMMs are used because they can accurately measure many features that cannot be captured accurately by hand-held instruments. Although CMMs can be automated, the inspection cycle times can sometimes exceed optimal time due to the number of features being measured per the program. This can slow shipments of final products or additional downstream manufacturing processes. The result is a bottleneck at the CMM.

The CMM is often programmed to check all the features of a part. Instead, many of the less complicated part features could be measured on an automated gauging system before the part is loaded into the CMM. The CMM program can then be shortened to only measure those features that cannot be captured via other means, leading to a reduced cycle time. Additionally, this could disqualify parts from being loaded onto the CMM if they are found to be out of tolerance based on the initial inspection.

In either case, the bottleneck at the CMM could be reduced.

Q-Span Automated Gauging System by New Scale Robotics

In all instances above, the Q-Span Automated Gauging System could be employed to limit or eliminate bottlenecks. As a Certified Systems Integrator for Universal Robots, New Scale Robotics specializes in the design and build of automated manual gauging systems that utilize existing, approved, and validated measurement procedures.

Unlike a CMM, the Q-Span System will move the parts to the necessary gauges just like an inspector would with manual instruments. The system will pick parts from a predetermined location and then move the parts to various measurement stations. Each station will measure the desired dimension, and the included software will capture the data and determine if the part passes or fails.

Upon completion of the measurement process the Q-Span system will then sort the parts accordingly. Measurement data can be exported in a number of formats allowing for importation into an existing Quality Management System (QMS) or Statistical Process Control (SPC) software system for analysis and storage.