The NPCA Best Practices Awards recognize industry best practices and improvements that showcase the best way to do a job, treat the environment, improve safety, save money and more. The program honors the precast industry’s sustainable, safety and lean manufacturing process innovations. The quality of the 2021 Best Practices Awards entries proves that NPCA Producer and Associate members are committed to manufacturing products in ways that improve life both inside and outside their plants. The entries were evaluated by the Engineering and Technology Committee, and the independent scores were tabulated to arrive at the following results:
Takt Time, Job Breakdown and Work Combination
Throughout its ongoing mission to enhance efficiency and reduce waste, Smith-Midland has implemented numerous lean principles into its production process. In 2021, the manufacturing schedule for a new product initially called for five associates performing various tasks to complete six panels in two hours. This procedure included too much waste as defined by lean manufacturing principles. Instead, Smith-Midland applied tools called “Takt Time, Job Breakdown and Work Combination” to streamline the process.
Through analysis, Smith-Midland established “Takt Time,” which is the available time divided by the customer demand of 20 minutes per panel. It then analyzed the “Job Breakdown” by timing the required tasks for each person and finding a total cycle time of 44 minutes. By dividing that by the Takt time of 20 minutes, Smith-Midland found it needed 2.2 people, rounded up to 3, to successfully complete the job. Finally, “Work Combination” is the result of analyzing the work sequencing and refining the process.
The result is the six required panels are manufactured in two hours using only three associates. This process resulted in 40% improved labor efficiency, reduced defects and engaged employees while creating a standard practice moving forward.
National Precast consistently seeks to facilitate product installation. As part of this mission, the company found that a challenge existed when adjusting at-grade precast concrete lids. Installers were required to utilize large equipment to lift the lids while using shims to make final adjustments. National Precast partnered with fellow NPCA member Rim Riser to install an engineered screw adjustment system that makes installation easier for its customers.
The system includes adjustable corrosive-resistant screws that enable installers to lift or lower lid corners using a screw gun and hex nut driver or a speed wrench. Once the top is set to the correct elevation and slope, the installer makes incremental adjustments to all screws to eliminate any remaining play or wobble. The installer then packs the gap between the precast top slab and supporting base with local agency-approved, non-shrink grout, concrete or mortar.
The system is easily cast into the lids at the precast plants using reusable pocket formers that are removed to leave the screw system accessible. This enhances the product’s functionality and eliminates waste associated with job-specific design and fabrication. It also enhances job site safety by requiring no heavy equipment or power tools to make grade adjustments.
Watts Water Flow
Winchester Precast is always on the lookout to implement new processes and programs to enhance product manufacturing efficiency. Often, these newly developed processes come as the result of careful analysis. Sometimes, however, necessity is the mother of invention. In this case, a specific predicament helped lead to the “Watts Water Flow” system.
While batching raw materials, the water flow meter started to miscount, so the batch plant operator began consulting the mixer wattage formula entered in the mixer program. When the slump or watts reached the preset amounts, he shut off the water. As a result, the mixes during the next days started to look better. Building on this, Winchester Precast integrated both systems in series they called the Watts Water Flow so the watts and the water meter prevented excessive water from being introduced into the mix.
The program monitors the fresh concrete flow by correlating the incoming grid voltage and motor amps for the specific mix design and shuts off the water before the flow/slump gets out of tolerance. This results in better concrete consistency.
Winchester Precast estimates a 45% improvement in controlling extra water, beneficial in achieving consistency of slump within batches. Winchester Precast has shared this programmed logic with other NPCA members to help them reduce fresh concrete variability and enhance their quality.