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Would You Drink it?

The rule of thumb when you’re looking at an aggregate for use in your mix designs is to pay attention not only to its dispersion across the screens, but more importantly the percentage of material retained on the pan. The retention on the pan passing the #100 sieve being usually around 6 percent or less. The reason for this is that the particle size passing the 100 screen is small enough that it can actually inhibit the crystalline growth that is a byproduct of cement hydration. The finer the mix, the more cement is needed to cover the aggregate particles. Another potential culprit for adding excessive fines, is your mix water. Ideally, your mix water should be potable as a result of it being either city water or has gone through a filter and softening process. Pulling water directly from a well could be as detrimental as having high fines content in your aggregates. If you’d like to do an in-house check, take a small amount of your mixer water and place it in a clear glass cup. Place a coffee filter over the top of the glass and let the water evaporate. When totally evaporated see what’s left, if it’s clear that’s great.  If it’s hazy or you can see deposits, you may want to address your filtration methods. For more information contact Production Specialist Mike Maroney.

Single Minute Exchange of Die

Changing a product mold in our industry is never a matter of “if,” it’s strictly a matter of “when.” As such, that change out time is critical to the production flow. We’ve seen operations that approach a mold change like a race-car pit crew during production and other operations that do it at the end of the shift while clean-up is occurring. The assumption is that it is a constant work in progress to transition from one product to the next in an efficient and timely manner.  Lean Manufacturing has a term for it; SMED, or Single Minute Exchange of Die. SMED is a process driven method of reducing changeover times through observation and evaluation of the steps involved. It’s a method discerning what can be done while the equipment is running or can only be done while the equipment is stopped. This will result in external and internal procedures that can ultimately cut down the time needed for a mold change without compromising unit quality. For more information contact Mike Maroney.

Batch Control Software

We have a tendency to focus on the mechanical aspects of our products as they go through the manufacturing process. From when they strip out of the block machine, transferring into the kilns, processing through splitters or antique finishing machines, and ultimately being palletized and rolling out of the plant. It’s all visual and sensory based with mechanical steps and audible cues. What we don’t think about though is really the heartbeat of the system, this being the batching control software that maintains the cadence of the operation. You can’t see or hear the calculations made on a batch-by-batch basis, but it’s critical to an operation’s success that the functions and steps are fully understood by personnel. Take the time to get to know your Batch Control Software, for more information contact NCMA Production Specialist Mike Maroney.

Hustle and Flow

The old adage is that the block machine only runs as fast as the batched mix allows. There are several aspects to this, but we are going to focus on one — water demand. All of us are aware of the water-to-cement ratios that govern cement hydration and workability. As an example, I run a fine textured architectural mix with a water-to-cement ratio of 0.59. The cement only requires a .22 to .24 water to cement ratio to begin hydration, everything past that is water of convenience. Along with or without admixture, the water of convenience allows the batch mechanically move from sub-hopper to feed drawer to mold in relatively fluid motion. There is no standard water cement ratio. There are ranges which are utilized based on the mix gradation. Rule of thumb: the finer the mix, the higher the water cement ratio. Whereas, my Architectural Fine Texture mix requires a .59 water to cement ratio, my standard sand and gravel blend may only require a .51 water-to-cement ratio. For more information, Ask Mike.

Color Matching

Eventually, one of your architectural salespeople is going to bring in a sample of concrete from another producer and ask if your operation can produce it. Don’t worry, because you may not be able to get an exact match, but you can certainly take a stab at it without tying up profitable machine time. Percentage out your closest matching architectural mix design to a 500-gram representative batch and adjust your pigment loading as needed. If you’ve got a vibrating table and a form, you should be able to simulate your consolidation. Put the samples on a blank pallet in your curing chamber and when the cycle’s complete, see how close you got to the salesperson’s sample. There are some nuances that need to be addressed when sample matching, so if you need help contact NCMA Production Specialist Mike Maroney.

Do you have a production question? ASK MIKE!

Smartphones and site solutions

A picture is worth a thousand words, but it’s also the best way to start the process of resolving issues on the jobsite. We all get photos sent to us to explain and demonstrate a situation that our customers are going through. The question is do you have a defined policy for whom to send the photos and a step-by-step, detailed process as to how that solution will be found. For more information on developing a documentation plan, please contact NCMA’s Production Specialist Mike Maroney.

Do you have a production question? ASK MIKE!

Cleaning house

If you scheduled your spring production correctly, your yard should be seeing some significant inventory turns due to the summer demand for hardscapes and do-it-yourself projects from the local hardware stores. As the inventory leaves, take some time to clean out the lots before you fill them again. It’s an ideal time to get behind the rows and clean up any debris or loose stretch wrap along the fence line. It’s also a great opportunity to take a look and see what inventory you made that didn’t take off as quickly as anticipated. Segregate it and get it out of your yard before you end up having degraded stretch wrap and aged pallet decay, potentially causing more than eyesore. For more information, contact NCMA Production Specialist Mike Maroney.

Do you have a production question? ASK MIKE!

Shift change and variability

Alan Perlis, a mid-twentieth century computer scientist stated, “One man’s constant is another man’s variable.” It’s a profound statement especially when considering the dynamics of operations running two shifts. More often than not, adjustments and settings are changed when one machine operator takes over for the next as every equipment operator has their own method of operation and adjustment, this is a fact, and it’s good as long as the information is being shared with the next shift operator. Once again, communication is the key to success and a way of maintaining consistency in production. For more information on variability and shift transition, contact NCMA Production Specialist Mike Maroney. Do you have a question about production? ASK MIKE.

Material flow and the feed drawer

If you start seeing a gradual decrease in the amount of material filling the mold box, don’t immediately increase your feed time. Stop the block machine in accordance with your safety policy and take a look at your feed drawer for buildup. When wet concrete builds up in the box due to hydration, your material flow can become restricted or clogged. For more information, contact Production Specialist Mike Maroney.

Runaway job orders 

A salesperson takes an order for 2,000 8″ split face units that are light tan in color. Having concerns about variability in the light tan color, the salesperson adds 5 percent to the order which bring the total number of units to be produced to 2,100. Either unknown or untrusted by the salesperson, the ordering system used has a built-in cull rate for that product and mix of 3 percent which effectively brings the number of units to be scheduled to a total of 2,163 units. At this point remember that the customer only needs 2,000 units and before the order has even been put on the schedule, the production order has increased by 8 percent. Two units are produced per cycle and placed in racks for curing which can hold 48 cycles which in turn means that scheduled order only needs 22 racks and 25 cycles to fill the order. The machine operator or plant manager decides to round up the rack requirement to 23 racks for just-in-case issues on the splitter, bringing the number of units produced to 2,208, an overall increase by the time curing starts to a total increase to the original customer’s needs by 10 percent.

Maybe there are some extremes here and maybe there aren’t, but the fact of the matter is that the example shows how easy it is to torpedo your own profit margin. When was the last time you went over the order process with not only your sales team, but also your plant personnel? For more information on capturing true costs, please contact Mike Maroney.