Perfecting Platform Performance

August 13, 2018 02:46 PM
 
Proper adjustment of flex-head small grain platforms is the key to minimizing grain loss and maximizing performance

Many combine operators hope to harvest soybeans at 6 miles an hour with less than 1 bushel per acre of grain loss. Achieving that goal requires careful adjustment and operation of both draper and auger-style grain small grain platforms.

  • Cutterbars are the starting point for optimum performance of both auger and draper platforms. Not only must sickle knives be sharp enough to snag a leather glove, but the rock guards and all wear points must be factory-fresh. Dull sickle sections, or rock guards with rounded edges where the sickle slides back and forth, gnaw rather than slice bean stems. Any vibration to a bean stem during its harvest can shake loose or shatter bean pods.
  • The angle of the cutterbar should be parallel to the ground or slightly downhill by 1 to 3 degrees. That angle is determined on older platforms by mechanical adjusters on the bottom, rear of the platform. Newer platforms adjust cutterbar angle by mechanically or hydraulically tilting the entire head. If the angle is too steep the cutterbar is prone to pick up rocks or gouge the soil. If the angle is such that the platform runs on the rear of its skid shoes, the cutterbar tends to cuts stubble higher, and drag stems and leaves under damp conditions.
  • Cutterbars must be straight so automatic header height control systems work properly.
    “Bent cutterbar supports can create high spots (in a cutterbar) that make it more difficult for the cutterbar to flex and follow ground contours,” says Matt Badding, John Deere tactical marketing manager for harvest equipment. “Bends in a cutterbar also increases wear to the knife.”
  • Check cutterbars by raising a platform 5 to 6 feet off the ground. Sight across the cutterbar from one end of the platform. High spots in the cutterbar suggest bent supports or brackets. Diagnosis can be tricky because small irregularities among cutterbar supporting components are magnified by the geometry of those components.  A 2” hump in a cutterbar can be the result of only a ¼” bend in a support frame or related component.
  • Older platforms with broad, wide skid shoes flex and follow the ground surface better if last year’s crop debris and dirt is cleaned from the tops of the skid shoes. Use compressed air to blow from behind the sickle toward the rear of the skid shoes. Material packed into that pivot point inhibits the ability of the skid shoes to flex and follow the soil surface, decreasing the sensitivity of the automatic header height control system.
  • Newer platforms incorporate an adjustable hydraulic system to control pressure of the cutterbar against the ground during operation.

Brent Kvasnicka, senior marketing product specialist for combines at Agco North America, says if operators increase pressure in cutterbar pressure systems, more of the weight of the cutterbar is carried by small hydraulic cylinders under the header frame, making the cutterbar less “heavy” and therefore less likely to “push” under damp or soft soil conditions.

If operators reduce pressure in their cutterbar pressure control system, Kvasnicka says less of the cutterbar’s weight is supported by the small hydraulic cylinders. The cutterbar becomes “heavier” but more flexible and therefore better able to follow surface irregularities, though the increased weight and contact with the soil surface can lead to “pushing” in damp or soft soils.

Once basic settings are made, adjustments specific to auger and draper platforms further optimize performance:

Auger Platforms

On auger platforms, reels should be initially positioned “back and down.” At its lowest position, a variable height reel’s tines should just clear the cutterbar if the center of the cutter bar is flexed to its highest point.

Adjust the reel rearward so its bats just clear the front of the cross-auger’s flighting. The reel should be positioned to continually feed and press crop against the auger so the auger can convey the material to the center of the platform.

Actual height of variable-height reels in the field depends on crop conditions. In down and tangled crops the reel may need to run at its lowest height. In tall crops under good conditions the reel may need to only run in the top inch or two of crop, but always to the rear and close to the auger.

Make sure all retracting fingers on the auger are straight, have smooth edges and that there are no irregularities in the auger’s flighting or main tube.

“Augers, especially full-finger augers, can flail a lot of beans,” says Kelly Kravig, Case IH harvest marketing manager. “A lot of beans we see hitting the windows of the cab that get blamed on reel shatter are actually related to the auger.”

Augers set too high, or too far forward, encourage crop to tumble around the auger, shattering pods. Augers should be set low and back, with 3/8” to ½” clearance between the edges of their flighting and adjustable stripper plates mounted to the floor and backside of platforms.

If a different platform is used on a combine than in previous harvests, match the cross-auger’s flighting to the combine’s feederhouse opening.

“Make sure the auger flighting stops at the outside edges of the opening in the feederhouse,” says Jeff Gray, product coordinator for Claas Lexion.  “You want the crop to feed into the full width of the feederhouse. There are extensions you can bolt onto or remove from the auger flighting to match the auger flighting to the opening of the feederhouse.”

Draper Platforms

On draper platforms best results come from running reels “forward and up.”

“We typically run the reel on a draper in good-standing crop with the fingers barely in the top of the crop,” says Jason Strobbe, North American sales manager for MacDon. “The goal is to have just a little pressure on the tops of the stems at the moment they’re cut to gently tip them onto the draper belt.”

Adjust belt speeds on draper platforms so bean stems move sideways toward the feederhouse as soon as they topple onto the belt. Slow belt speeds encourage clumps of stems to build up at each row before the belt moves them sideways, which then feed into the feederhouse in bunches that degrade threshing and separating efficiency of the combine.

Excess belt speed can center-feed the feederhouse. Fast-moving bean stems from each side of the platform collide in the center of the platform and form a narrow windrow that feeds only into the center of the feederhouse. Belt speeds should distribute the material across the full width of the center belt to optimize even feeding into the combine’s threshing system.

Proper adjustment of small grain platforms prior to harvest can minimize grain loss to less than 1 bushel per acre. Understanding where grain losses originate is critical to optimizing the performance of not only grain platforms, but the combines behind them.

“You can adjust your combine’s rotor speed, concave settings, cleaning fan speed and sieves all day long and none of those adjustments will fix grain loss problems at the header,” says Kvasnicka. “It’s necessary to get out of the cab and spend time looking at the ground, from the front of the machine all the way to the back, to see if the loss is from shattering due to a dull knife, because of reel position, or maybe it’s related to the action of the auger.

Don’t blame the combine for problems created at the header.”

 

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