Blog posts tagged with 'engineering'

As the food industry responds to animal welfare issues, many producers have started to consider alternative options to stall-based gestation systems. We took a few moments to speak with Hog Slat’s national sales manager, Fritz Richards, about group housing systems.
Can you describe the options available and the advantages and disadvantages of each?
Hog Slat first took a hard look at the Electronic Sow Feeding or ESF systems. Sows are housed as groups and fed in stations that identify sows individually by means of RFID ear tags. This type of equipment seemed to offer slight advantages that would offset some of the management tools which producers would lose going to group housing from stalls. Such as the ability to feed animals as individuals and maintain dynamic farrowing groups. We looked at both domestic and international systems, touring and speaking with experienced growers. There were some differences that came to the forefront.

Like?
This type of system is a major paradigm shift for US producers. The US industry has developed a very straight forward system of handling gestation sows. Sows are weaned into a stall, bred there and sow condition is managed by individual feeding. ESF is a completely different management style. First, the animals must undergo a two to four week training process with up to five percent of them eliminated as untrainable. Second, because computers, scanners, RFID tags and low voltage lines are necessary for ESF equipment a highly trained staff is required to operate the system successfully. With many production systems experiencing high turnover of farm staff, it becomes very difficult to perform the necessary maintenance and training.

Where do you see ESF working best?
Farms where the owner works in the unit every day and is able to maintain and repair the equipment in-house. The U.S. landscape is not like the situation we saw in Europe where as many as six service technicians are available in an area the size of a U.S. county. Getting timely repairs when the equipment is down should be an important consideration when considering ESF systems.

What other options have you looked at?
Free Access Stalls. In this system, the sows are housed in groups but are provided with access to individual feeding stalls. The stalls have a lockout mechanism on the rear gate that allows sow access and prevents other sows from entering. She is able to exit the stall at any time to go back in the pen area. Most designs feature an option for the herdsman to lock the sows in the stalls for treatment. We feel this may be the ultimate sow housing system.

Are Free Access Stalls available from Hog Slat?
We offer this equipment to producers, but, they need to remember that this is the most expensive option they can install. The square footage requirements per sow are high, (as much as 37 sq ft per sow) and the stalls with a locking mechanism are more expensive than a standard gestations stall.

What other options are available?
Floor feeding in pens actually predates stalls. This system is designed with five to eight sows per pen, and the feed is dropped directly on the pen floor. This system is successful if managed correctly. Grouping of the sows by size is critical as the strongest animals tend to get the most feed. It is the lowest cost alternative to gestation stalls.

What seems to be the most popular option?
Stanchions are the most popular system we see for new and remodel projects. This is group housing with short dividers or stanchions to protect the individual sow at feeding time. This design lends itself to a wide range of group sizes with a lot of flexibility in pen and building dimensions, which is important with remodel projects.

Why do you think it is so popular?
Stanchion production methods adapt well to current U.S. production practices. A farm’s current staff can manage a stanchion system because it utilizes the same feed delivery system and penning equipment as they are currently using.

What criteria are used in designing a stanchion system?
The first decision is how many square feet per sow will be allocated. Obliviously, square footage in the building is expensive, and this can range from 17 to 24 square feet per animal. This is a business decision each producer must weigh against projected welfare regulations.
A group sizing of 10 to 20 head per pen is common. Equipment is standard 40-inch high rod panels with 18” long divider stanchions, creating a feed space for each animal in the pen. The stanchions are open rod style set at 18” to 21” width. Experience has shown it is not necessary to use solid dividers on the side or front of the stanchion. The rod style protects the ears and head of the sow from aggressive animals and doesn’t restrict air flow as much as solid panels. In addition, rod style penning is more cost effective and has a longer life span.
We also design a breeding area with stalls equal to 45 days worth of sow holding capacity. Sows are weaned into this area until bred and formed into gestation groups.

How is the stanchion system managed?
Sows are fed using an automated feed system with individual drops. Sows anticipate each feeding and start lining up before the feed drops. You don’t see much shuffling between stanchions as they become conditioned to eating their portion and realize the other feeding slots will not have feed after they finish. The earliest systems utilized a trickle feed system where over a longer time, small amounts of feed were dispensed to hold the sow at their feeding space. Trickle feeding was proven to be unnecessary and just added additional cost to the scheme.
While the sows are eating, a herdsman moves along the alley noting animals that are not at the feed trough. He can mark them for later treatment or movement to a hospital area.

Are there any disadvantages?
Yes, animals cannot be individually fed. Sows that “fall out” of a group because of sickness or injury have to be removed to a hospital pen or stall. Despite the disadvantages, this has been a popular choice for many producers desiring to move into group housing.

How many stanchions have been installed by Hog Slat?
Hog Slat has built and installed over 150,000 spaces of stanchion housing in the U.S., from individual farms up to large production systems. We have gathered a lot of field experience completing those projects and can help any producer considering group housing systems.

As livestock and poultry housing became larger and we developed more sophisticated feeding methods, the use of multiple bins in tandem was more common.  While this set-up allowed for greater flexibility in feeding, the front bin of the pair was often prone to plugging.

If we look at the anchor bearing that is present in the rear bin, one would notice that it has a restrictor tube over the shaft.  This restrictor tube fills the core of a flexible auger and prevents feed from filling the core and overloading an auger. This restrictor is not present in the front bin.  When the slide is opened feed overloads the system faster than the auger will move it away.  The obvious solution is to cut the opening down by closing off the slide to restrict feed flow.  This can cause other problems as a feed flows tends to flow only down one side of the bin.  A better solution is to use baffles in the boot to restrict feed flow.  This works to prevent plugging but can cause feed bridging in the bin.

Over the last several years Hog Slat developed and tested a unique solution to this problem.  The final product is called the Extended Anchor Bearing.

Described simply, the Extended Anchor Bearing extends the rear tube restrictor to the front bin.  The auger core is filled in and feed cannot overfill the system.

The Extended Anchor Bearing ships complete with a 14’ restrictor tube, replacement bearing and fastening hardware.  The 14’ restrictor tube is cut to length and inserted it the auger core.  The new bearing is installed and the auger reattached.

If an extended anchor bearing would help you prevent auger overload, visit the Hog Slat website to find the model that fits your flexible auger fill system.

One of the newest tools utilized by Hog Slat’s engineering group is a 3D printer.  About the size of a small refrigerator, the 3D printer generates plastic prototype parts from computer generated 3D models.

A member of Hog Slat’s engineering group, Andrew Mitchell took a few minutes to show us how it worked.

“Here’s a feed line drop adaptor we designed for the Grow-Disk™ system,” explained Andrew as he pulled up a 3D model on his computer screen. “We needed to develop a model that would work on both metal and plastic tubes.  Since these tubes have slightly different diameters, we wanted to test the fit before proceeding with molding.”

The cube in the screen represents the printer’s chamber, and the white image is a digital model.  The program divides the object into digital cross-sections and the printer builds the object in layers.   The printer makes multiple passes spraying very thin layers of plastic until the final shape is complete. 

“You can almost compare the printer to a giant glue gun that accurately places liquid plastic down in precise layers,” Andrew said, “The process can take from several hours up to several days depending on the size of the item.  The maximum size part we can print is 10” x 10” x 12” tall”

“We were able to take the prototype drop adaptor and test it on both the metal and plastic feed tubes. We made a few small dimensional adjustments and proceeded with complete confidence that the final part would fit as we intended.”

Frank Harris, Head of Hog Slat’s Engineering Department, spoke with us about the development of the GrowerSELECT product line.

What is the focus of the GrowerSELECT product line?

Hog Slat wanted to directly source products to reduce final cost to the end user. We knew we could lower the cost if we reduced the number of people that handled a product, and in many cases improve the quality.

Replacement motors for fans and feed systems were the first items we started to direct source.  OEM Fan and feed auger companies do not produce their own motors; they all buy from the same motor companies.

We did not just buy off-the-shelf motors. We specified certain improvements in the motors based on our experience.  For instance, one problem according to our service department was motor shaft breakage.  We changed the shaft diameter blend radius and specified a hardened shaft of 1144 steel. We eliminated the problem.

Some people may have the perception that GrowerSELECT products are just cheap generic copies. How would you answer that?

I am not going to tell anybody that we invented feed systems or fans. However, in almost every case we are able to look at existing products and make improvements.

We evaluate every item developed for the GrowerSELECT lineup in three different ways.

First, from an engineering standpoint.

Can we make this product out of different material? Can we make it easier to manufacture?  Can we change the shape or size to eliminate problems?

Second, we evaluate from a repair standpoint with feedback from our service departments.

What are you fixing out in the field?  Where is this product failing?  What would make the product easier to service?

Third, and most importantly, we evaluate from our customer’s standpoint.

Is this the right product? Is this the right size?  What is giving you the biggest headache in using this product?   What changes would you make?

After gathering this information, we conduct the Process Failure Effect Mode Analysis or PFEMA.  Simply put, this is a logic method for determining why a product fails and how to correct it.  We document the process and can refer back to it when problems arise.

We then create detailed 3D computer models of the proposed product and subject it to computer-simulated stress tests.

Wait a minute; you can test the product before it is even built?

Yes, here’s a good example.  When we first designed the blue plastic hopper for the SowMAX, we did not have a lip at the top.  When tested via computer simulation, we realized it might crack when impacted, for example if a feed cart banged into it.  We added the lip to strengthen the hopper and eliminated a potential problem.

Another example is the GrowerSELECT® clear upper boot, injected from impact-resistant polycarbonate.  It does not have to be as thick as plastic boots used by other manufacturers to have a superior breaking strength.  We were able to “tweak” the material thickness and avoid adding unnecessary additional cost to the end user.

The next part of the process is to send the drawings to a manufacturer and order sample parts to test against a quality control process known as PPAP or Production Part Approval Process.

Okay, what does that mean?

It is the same quality control process the automobile supply industry uses.  It means we take the sample products and measure them against the drawings we created.  We particularly identify those measurements most critical to the quality of the product.

Once we are satisfied that the sample batch is correct, we then order a small production run.  This first-production run is then field tested.  Our service group installs them on farms, and we monitor the results.

After field-testing is completed, we release the product to manufacturing.

Before receiving those released products into warehousing, our Quality Control department conducts a series of QC checks.  Keith Riley, QC department head, creates an Incoming Inspection Document for each item.  This establishes a benchmark of quality checks used to test production parts.  This is not only done the first time we receive the product, but every time that product arrives from the manufacturer.

How many people work in Hog Slat’s engineering department?

We have nine engineers and six Quality Control members. We have a good core of experienced engineers with several younger guys that we have hired…I like to say we have just the right blend of “gray hair” in the group. I have to say the younger guys have a great “toolbox” they bring with them. They are contributing with new technology.  A good example is the 3D printer we recently added to the department.  It is allowing us to perform some things we had not been able to do before.

What are future goals for your group?

Continuous improvement of products.  Just because we have a product developed doesn’t mean we quit trying to make it better.  We think we can improve motors. One of the principle reasons we are able to offer a two-year warranty is that we have such a very small percentage of motors returned under that warranty. But, we have some ideas that will improve these motors even more.

Hog Slat has a very unique position in the industry.  We are responsible directly to the end user.  It is our own people installing and servicing the products we sell.  We cannot pass off problems to someone in the supply chain; we are the entire supply chain to the end user.

We have access to company farms to test new products.  We have feedback from our own service crews.  Our goal is to use these resources to improve product offerings and get those improvements to the market faster.

One of things I think we are the best at is identifying the optimum place in the world to manufacture a product.  We are not just throwing everything to Southeast Asia.  In fact, we have moved several products back to the United States. A good example is Classic Flood feeders, we started overseas but now these parts are molded in the U.S.

We do a lot of final assembly at our locations in Clinton, NC and Humboldt, IA.  We source items from the U.S. and other parts of the globe, bring those components in to test, then assemble the end products.  Using this process we have more control over the quality of the final product.