The quality lab is a critical component to manufacturing companies, especially when preparing parts for production, routine inspection and also product development. But for some manufacturers, once a part is production-ready, daily inspection can be long and laborious with tasks like fixture changes and manual part loading. How can companies stay competitive when faced with such challenges?
Automation is the simplest and most productive solution. Consider automating and moving your coordinate measuring machines (CMMs) to the shop floor. This can reduce throughput time by creating inspection efficiencies, as dedicated tools and fixtures from the quality lab can be used on a production line CMM or in a shop floor measuring enclosure.
Using data to justify productionizing inspection
Productionizing inspection needs absolute data to justify such a momentous change. Some machine shops may hesitate when considering budget, time, space and training. The best way to prove out costs is with the already-existing off-line inspection room or quality lab. “Metrologists can gather operational data on their quality systems as ammunition to justify the integration of inspection and production,” says Brian Johnson, global project manager, ZEISS Industrial Quality Solutions. “This is made possible with industry standard data transfer tools, like MTConnect.”
MTConnect is a free, open manufacturing protocol that offers domain-specific vocabulary and data models, is extensible, and integrates with other standards by design. This semantic language can be used for the one-directional exchange of structured, contextualized data between shop floor equipment and software applications used for monitoring and data analysis. With uniform data, manufacturers, developers and integrators can focus on useful, productive manufacturing applications rather than data translation.
Every manufacturer needs factory-monitoring software, but what does this have to do with CMMs? “MTConnect can communicate CMM events to a customer’s enterprise resource planning system or machine-monitoring software,” says Scott Lowen, software product manager for ZEISS Industrial Quality Solutions.
These events include operator log-on and off, measurement plan start and finish, and CMM errors and collisions. “Adding MTConnect to CMMs helps show their utilization,” Lowen continues. “Observing the inspection equipment in the lab can show how setup time can be reduced up to 50%.”
Getting inspection equipment closer to the process can reduce scrap by qualifying parts during production rather than at the end.
Implementing an integrated manufacturing shop floor
If you’re considering automating CMMs, start in the lab and get it right. Once moving inspection to the shop floor can be justified, steps need to be taken to implement this integration. There are three stages that need to be considered: planning, continuous monitoring and anticipating future changes.
For a successful integration, the following factors should be considered to prevent future system failures:
- Proper utility
For layout, it’s as simple as ensuring that a service technician has access to the CMM.
Many manufacturers have experience with robots and conveyors, and think they know what it takes to set up a quality-integrated manufacturing cell. Sometimes the result is an unintended lack of access to the CMM which can cause long delays for the entire production line when maintenance or calibration is needed on the CMM. If it takes a week to fix the inspection equipment, that’s a week in which chips aren’t flying and the productivity you’ve invested in is costing you.
To avoid this, all devices must be laid out for access in a floor space efficient, but still accessible, environment. This can be done in the planning stages of implementation by using CAD software to create a three-dimensional model to visualize the production cell. This also allows you to run simulations of the process before configuring a cell, which can help avoid future reconfigurations and down time.
When planning for additional CMMs and other future changes, think beyond the current layout, environment and employees.
Environment is also a critical factor, especially since concerns are different for CNCs and CMMs. Air filtration is vital to handle all the particulates in the air. Shop floors also tend to be dirty and covered in oil. Highly-calibrated inspection equipment can be affected by these elements along with vibration and temperature. Along with implementing vibration dampening and enhanced temperature control, a shop-hardened CMM is the best solution. For harsh environments, offerings with an IP54 rated cabinet can maintain accuracy over a wide temperature range—from 15° to 40°C—and increase utility.
As well, safety must be maintained. Generally, CMMs are considered safe for interaction. Putting them on the shop floor, however, changes the dynamic of equipment and worker. When a CMM is implemented on the production line, it can create hazards for the operator who is trying to manually feed or check parts. Don’t think of CMMs the same way as when they are in the quality lab. On the shop floor, CMMs should be treated like a CNC machine and the proper barriers should be in place.
Finally, make sure there is the proper equipment to handle automation. There aren’t just software considerations but also hardware. Shops that have been using the same equipment for 40 years or are running computers on outdated operating systems should consider updates across the board. Furthermore, preventative maintenance becomes even more critical when automating production and inspection, as something as simple as forgetting to replace a backup generator’s batteries can result in damaged equipment and corrupted software if a power surge occurs.
Automation can be a job creator and value-added opportunity.
Utilizing monitoring software for continual process improvement
Once you’ve pulled the trigger on CMM automation, MTConnect can play another role in continuous monitoring. Traditionally CMM monitoring software is used offline. There are, however, MTConnect adaptors that when paired with CMM monitoring software, can communicate status and events to customer ERP systems in MTConnect protocol. The result is:
- Maximized manufacturing efficiency
- Real-time trend identification
- Improved employee efficiency
- Alerts/notifications that a CMM is down or finished a program
- Comprehensive reporting including OEE (Overall Equipment Effectiveness)
OEE is particularly significant, as it is the gold standard for measuring manufacturing productivity. “It identifies the percentage of manufacturing time that is truly productive,” says Lowen. “An OEE score of 100% means you are manufacturing only good parts, as fast as possible, with no stop time.”
Many companies struggle to report OEE correctly because few are using the part quality component of the OEE calculation. Part quality is left at 100% because most factory monitoring software doesn’t use CMM results to evaluate part quality. And this is because CMMs do not offer automated methods to report good/bad parts to the factory monitoring software. If you want to calculate OEE correctly, pair your CMM monitoring software with an MTConnect adaptor.
Planning for the future
After a successful implementation, it’s natural to consider expanding on your CMM inventory. “We get the request from current customers wanting to report CMM utilization to justify the need for more CMMs,” says Lowen. Some machine-monitoring software will calculate machine tool downtime when manufacturing is waiting on quality, such as when a machine tool is on hold waiting for a first article report. If the CMM was added to the factory monitoring software and its availability correlated to a part, a plant manager would have empirical data of machine tool down time directly related to lack of CMM availability. This would better justify the need for another CMM.
When planning for additional CMMs and other future changes, think beyond the current layout, environment and employees. Is your shop expanding? You need to prepare for the possibility of new equipment. Is there room for new CMMs? What about the robotic loading and unloading and built-in dual-pallet systems that accompany automation? Where are ventilation systems located and will they be blowing on new CMMs?
With all these changes, there’s also the human factor to consider. On the one hand, more efficient routines make for more efficient metrologists. Automating inspection can reduce lead time from production to inspection together with reduced setups between inspections. This increases the availability of production equipment and creates inspection efficiencies. On the other hand, some view automation as a job killer.
It doesn’t have to be. Automation can be a job creator and value-added opportunity. “If an operator isn’t sitting around waiting to switch out parts, he can be performing other tasks such as visual checks, routine cleaning of stylus tips and spheres, running stylus qualifications, cleaning and replacing filters, and keeping granite and guideways clear of debris,” says Johnson. “Automation makes the metrologist more than a machine operator, freeing up their valuable skillset to be proactive, analyze data and build more process efficiencies.”
With uniform data, manufacturers, developers and integrators can focus on useful, productive manufacturing applications rather than data translation.
The case for an integrated manufacturing shop floor
With CMM automation, look at the whole value stream. Getting inspection equipment closer to the process can reduce scrap by qualifying parts during production rather than at the end. Creating a repeatable, user-friendly inspection process with traceable data can minimize quality issues and optimize production.
This may require an adjustment period. Getting operators excited may take time. But as Johnson says, in order to build quality products in a timely and safe fashion, you must be forward thinking.