R300: From Roll-up to Stacker Q&A

FireFly AutomatixEducation, Product Information

You work hard to produce quality grass, and you rely on your harvester to stack as much of that grass as possible into neat, stable blocks. Steve Aposhian, FireFly CTO, explains how our technology allows the R300 to roll and stack turf with unmatched durability, quality, efficiency, and productivity.

R300 with pallets of mini-rolls

A critical component of any roll machine is the ability to make consistent, tight rolls. It should be gentle on tender turf, yet robust enough to roll up even the stiffest of grasses. At the same time, the flap needs to be placed in a predictable, consistent position. In addition to this fundamental functionality, at FireFly we wanted our roll-up system to be adaptable to any condition without having to completely reconfigure the mechanism. These lofty goals drove our uncompromising commitment to building a unique roll-up system that is extremely durable, simple to use, and easy to maintain. After extensive testing, we’re proud of the result—the quietest and most adaptable, durable, and consistent roll-up mechanism every built.

Why are there two flippers?

The R300’s roll-up starts with FireFly’s exclusive compound flipper. This is not just two flippers; it’s a complementary flipper system that works together synergistically. The flippers are spaced at exactly the right distance and on different rotational centers so that one flipper starts the edge, and then the other one helps curl it over on this uniquely designed mechanism to start a tight, consistent roll. At the same time, this revolutionary flipper system is mechanically self-adjusting. As sod thickness changes, it always provides the proper lead-in to the roll-up ladder. The developing roll passes under a sensor that detects where the flap is. This innovative design delivers a very repeatable start of a roll, which anyone that has ever operated a roll machine knows is key to consistency.

What’s the purpose of the longer passive roll-up?

The next segment of the roll-up is the flexible, passive roll-up. This unique rubber and stainless-steel section of the rollup is easily adjustable—without tools—to any type of grass, density, and strength. We opted for a much longer passive section than any other manufacturer to allow more gentle handling. The flexible belt with cleats cradles the roll, providing consistent, uniform contact without causing any tearing action. In addition, a series of sensors here help detect the edge of the flap for automatic adjustments.

How does the R300 get such a consistent flap across conditions?

Once transferred to the active rollup, the roll passes under more sensors that measure the roll—its shape, diameter, position, and length of flap. The computer then calculates how to finish the roll with precise flap placement.

Even as the roll may change length or thickness, the flap is very consistent without the need for adjustments. When you’re harvesting on a slope, the slope changes the angle of the conveyor, which could slightly affect the flap position, but not on the R300. It will still make a very repeatable roll from one end of the field to the other, even if the angle of the conveyor is changing because the field is on a hill.

Because the rollup is so precise, you can easily change the roll length. Say you’re cutting 60-inch rolls for one customer, and 48-inch rolls for another customer. Most times, the only setting you’ll need to change is your chop length.
uniform stacks of rolled turf harvested by FireFly Automatix R300

Why is the R300’s roll-up so quiet?

The R300’s active section of the roll-up is another system driven by electric servo motors. The roll-up utilizes premium materials like polymer bearings and stainless-steel ladder cleats. There aren’t any metal-on-metal pivots clanking together here—just quiet, consistent motion. And smooth and quiet systems last longer.

How can the R300 cut so fast?

The R300 is the fastest single-head roll machine on the market, and in some conditions, it even rivals the productivity of double-head machines—at a much lower cost of ownership. We can cut over 2 mph with this machine in many conditions. We have customers cutting at 2.2 mph, or 7.2 square feet of grass per second. Check out this video I posted:

There are several processes that the R300 can complete at high speeds, enabling that speed possible: the transfer of rolls from the roll-up to the accumulator is done very smoothly, even at high speeds; the ability for us to synchronize our accumulator with our stacker, even at high speeds; and the extremely smooth and controlled motions of our stacker, even at high speeds.

One place where we gain speed is in our patented method of transferring the rolls to the accumulator. When a harvester runs fast, the roll has a lot of speed coming out of the roll-up. If you add even more speed to it by dropping it onto a conveyor, it’ll have more of a tendency to loosen up. Most other manufacturers’ machines do just that—the roll falls down onto the accumulator, and various techniques are employed to help keep that roll from coming undone, including limiting speed.

The R300, on the other hand, can transfer rolls at high cutting speeds because they are lifted onto the accumulator. Once the roll has been measured and completed, the conveyor actually reverses to help move the roll more smoothly onto the accumulator. After the roll is ejected, we use gravity to our advantage to again slow the roll. The accumulator sits at a higher level than the main conveyor, so the Sho Arm transfers the roll in an upward trajectory. This design is one factor behind the R300’s capacity to run at higher ground speeds than any other machine.
Placing the accumulator and Sho Arm at a higher level also shaves off time because the stacker doesn’t have as far to move when lifting rolls onto tall pallets. Pallet change times are also faster because the pallet injector can inject pallets at much taller heights.

An additional component of the R300’s high productivity is its accumulator synchronization. Unlike many other harvesters, FireFly’s accumulator doesn’t need to have any rolls on it to get it started. The stacker can also pick up rolls while they are moving on the accumulator, because the servo-controlled conveyor is automatically synchronized with the stacker for FireFly’s patented pick-up process. This means there’s no limiter to how fast you can transfer rolls onto the accumulator, thereby speeding up harvesting capability substantially.

Can it really scrap without stopping?

Yes! When a roll is rejected, the Sho Arm moves up and allows the scrap roll to exit without being transferred onto the accumulator conveyor. One really nice feature of the Sho Arm is that it can scrap a roll without moving either the accumulator conveyor or the main conveyor. This means that you can scrap while continuing to cut, and you can scrap while you are stacking.

What are the benefits of the electric servo systems?

In a nutshell, electric servo motors improve quality, consistency, speed, durability, and the range of grass and conditions that you can harvest. The motors that control the R300’s systems are the same kinds that you will find in industrial machine tools, such as machining centers and lathes. They yield very smooth and precise movements. And just as smooth motions are gentle on grass, they also drastically reduce the wear and tear on the machine.

The repeatability and consistency of the R300’s roll-up and stacker are second to none. As its components speed up and slow down, the rolls are undisturbed.

As I’ve mentioned, there’s an especially important reason why the R300’s accumulator is driven by electric servo motors. This system is the reason that FireFly has the only machine on the market that can pick up rolls while they’re moving. Those of you that have operated roll machines understand that the basic bottleneck of a roll machine is its ability to pick up rolls. The rate that rolls transfer from the roll-up to the accumulator obviously depends on how fast you’re moving through the field. The faster you go, the faster the rolls are coming. On any other roll machine on the market today, the stacker mechanism must come down, pick up the rolls, and get out of the way in less time than it takes for that next roll to be transferred. The R300 is the only roll machine on the market that doesn’t have that speed limitation. Because of its ability to perfectly synchronize the accumulator conveyor with the stacker—front and back—it can pick those rolls up while they’re moving without disturbing the rolls at all. It’s a perfect synchronization between the two movements. The electric servo motors give the R300 that ability, and the patented synchronization capabilities of our stackers are so key to our harvesters, in fact, that we’ve given them the name “SynchroStacker.”

In addition, electric systems are so much more efficient, only drawing the precise power needed. This reduces the engine size needed, which in turn uses much less fuel.

How much greasing is there?

The grease intervals are very light on FireFly machines. There are no grease points anywhere on the R300’s roll-up mechanism. We use stainless-steel flippers, and all the joints on this roll-up use polymer bearings on stainless-steel pins. FireFly pioneered this in our industry, and we still lead the way in using this technology to its fullest extent. The result is incredibly low daily maintenance of this machine.

You will need to grease your cutter head, conveyors, and a few bearings here and there, which are high-quality and off-the-shelf. However, because of our extensive use of both sealed bearings and polymer bearings, there are probably only 1/10 as many grease points as other machines on the market. This means there is minimal maintenance on a day-to-day basis.

Why does the R300’s stacker use corkscrews?

Perhaps one of the most dramatic innovations of the R300 is the revolutionary stacker head, including its exclusive helical pick-up screws. We selected a corkscrew-type mechanism because of its extremely high vertical holding force—much stronger than something like a spear or a hook. This means we can pick up even the most tender of grass rolls with amazing security, as well as penetrate very stiff clay soils—even rocky soils. The center stake provides additional stability of the roll as the counter-rotating screws go into it, so the stacker can hold rolls that would typically fall off any other machine. At the same time, they hold the roll in a way that also provides a lot of horizontal holding force and can therefore press down on the pallet, compressing the layers together for more stability.

Corkscrews, however, pose a little bit of a challenge. Anybody that’s ever tried to drill a hole and tap it for threads knows you must be perfectly synchronized going in with the vertical and rotational movement. This challenge is solved with FireFly’s electrically driven mechanisms. In fact, because the R300 has the highest performance, most technologically advanced control computer on any harvester in the industry, it does this reliably and effortlessly. We can precisely synchronize the pitch of that screw with the vertical movement of the stacker head, so it doesn’t disturb the roll at all and goes into the roll very cleanly.

The screws are made from high-strength spring steel, which is about ten times stronger than the regular steel commonly used. If you were to hit a big rock, which I’ve done before, they usually just bend and spring right back, so, they’re exceptionally durable.

How does the applied down pressure compare to other harvesters with spears or hooks?

It’s actually difficult to apply down pressure with hooks. Spears can apply lots of down pressure because they use the top of the stacker to push on the rolls. The R300’s mechanism uses the horizontal holding force of the screws to apply down pressure to the stacker, and we can apply a lot of pressure on that stack—well over a thousand pounds per stack—or the equivalent to a ton over the whole layer.

What makes the R300’s stacker unique?

Everything in the R300’s stacker is electrically driven. There aren’t any hydraulics on the stacker at all. This is technology that FireFly pioneered with our slab machine, and we’ve been perfecting it now for over eleven years. We have logged many hundreds of thousands of hours of stacking time and refined this technology for use in sod harvesting machines. Slab harvesters have a particularly challenging situation. Unlike a roll machine, where we’re picking up 50 square feet of sod at a time, on a slab machine, you’re maybe picking up eight square feet at a time, and so that stacker is moving back and forth literally over a million times a year. In an equivalent roll machine, cutting the same amount of sod, it’s moving something like 150,000 times.

In engineering and mechanical design, when you start getting mechanisms with over the magic number of a million, all kinds of new design considerations for fatigue come into play. We needed the stacker on our slab machine to hold up to millions and millions of cycles. Using an electric stacker gives us the ability to move very smoothly. Fast is important, of course, but also, the accelerations and decelerations have to be very tightly controlled to avoid high stresses in the system. Electrification has other benefits beyond durability, including higher productivity, consistent rolls, and much lower fuel consumption and power requirements. The electrically driven stacker is also completely immune to temperature changes. It does the same move, time after time, whether it’s hot or cold.

FireFly’s exclusive scissor vertical axis is another unique feature of the R300. This mechanism has the best rigidity and very low maintenance. All the stacker’s movements ride on smooth glide polyurethane rollers. As the machine gets thousands of hours on it, it will stay stiff. In addition, its wear components are replaceable, with nothing welded onto the chassis.

The R300’s gantry style stacker has many advantages over a robotic arm style: first and foremost is strength and rigidity. The fully supported gantry of the R300’s stacker is by far the most superior structurally, is able to move much faster with less power, and overall is much more simple and lower cost to maintain.