September 5, 2017 at 3:32 p.m.
TLC for your TMR mixer
"Preventing a TMR breakdown through regular maintenance is much better than finding yourself with a half-loaded tub and an empty feedbunk ... Trust me. I've been there," said Matthew Digman, an agricultural engineer at the U.S. Dairy Forage Research Center, Madison, Wis.
Digman talked about feed mixer maintenance during the recent Arlington Dairy Day in Arlington, Wis.
Applying grease is a good place to start. Digman said greasing should be a once-a-week job, rather than one that's done just once or twice a year.
TMR mixers grease points include universal joints, drive-line bearings, door guides and linkages, Digman said.
"If your machine relies on grease lines, take some time to follow each one to its delivery point," he urged. "Check both lines and fittings for leaks. There are also a few yearly grease points on these machines, such as the repacking wheel bearings and load cell mounting tubes."
Since some of the greasing will take place near the mixer's tires and wheels, it's a good time to also check tire pressures. Digman said the right tire pressure helps tires last longer and wear evenly.
Go to the chains next. Clean off dirt and old grease, since they can make drive components wear out faster.
Remember to check the sprockets for excess wear, or signs that a chain hasn't been riding properly. Such a sign could mean that a chain needs tightening, that it has become elongated, or that a sprocket isn't correctly aligned.
Mixing feed creates dust. Knowing that, some mixer manufacturers use automatic oilers or oil baths that partially submerge the chain in oil.
The reservoir for an automatic oiler might need filling, and the oil dripper or brush needs to be in the right spot above the chain, Digman said. A high level in the automatic oiler reservoir might mean that water or feed ingredients contaminated the oil. If that's the case, make sure the oil bath is sealed properly and that the shaft sales are in good shape.
Along with roller chains, the apron chains need to be adjusted correctly and tracking well, Digman continued. Adjusting them usually involved taking up the slack on each side of the conveyor until the slats move only a specified distance from the conveyor floor. The mixer's operator's manual contains the specific information.
Remember to replace all the shields that have been taken off. Besides helping with safety, they keep dirt and feed off drive lines and chains.
Digman called a mixer's planetary gearbox the "heart" of the machine. He advised checking the oil level and following the manufacturer's recommendations on oil change intervals. In most cases, a yearly oil change is recommended.
When the oil has been drained, look at it for signs of metal, moisture or dirt. If something seems wrong, take a sample of the oil to the mixer dealership for testing.
"I would, at the least, opt for the viscosity, silicon, and additive breakdown tests," Digman said. "These will indicate the levels of water, dirt and degradation in the oil."
Augers, paddles, hopper
The next places to inspect are the augers, paddles and hopper. The ingredients in feed can cause wear on all these parts.
"Wear can show up as thin or bent auger flighting, thinning or holes in hoppers, and the rounding of knives and clean out elements," Digman said. "Your operator's manual will spell out tolerances that must be maintained for critical mixing components.
Replacement parts are available for components that tend to wear. Some mixer manufacturers offer products that can be welded onto hoppers and augers, to help keep wear at bay.
Moving to the electrical system, check the lights and the scale. Clear debris from wires and make sure they are tied up and tucked out of the way.
"If wires run down a 'chase' tube, make sure it is clear of debris," Digman said. "These tubes can become high-rise apartments for rodents. If you suspect a nonpaying tenant, steel wool can be stuffed partway down the tube as a deterrent."
If a wire for a load bar or weigh cell is damaged, take pains to be careful splicing it, Digman said. It might even be a good idea to send the weigh bar back to the manufacturer for fixing.
"If you do need to splice a cable, take care to use solder and heat shrink, to ensure that moisture is not introduced into the connection. Because the scale indicator predicts weight based on changes in resistance in the weigh bar, changes in cable resistance can throw off the calibration or cause erroneous readings," Digman said.
Now it's time to take the cover off the junction box and look for corrosion. This box should be sealed so it's water tight.
See that all the wires in the junction box have tight connections. The weigh bars themselves don't need much maintenance - just a dab of grease in the receiver tube. But that's not the case with load cells.
"Load cells usually use a check arm to keep the mixer secure to the truck or trailer without transferring any weight to the frame," Digman said. "The spherical joints of these arms should be tightly attached to the mixer and truck or trailer frame, but the arms should still be free to move around that spherical joint."
Digman suggested using oil or grease plus a rubber mallet to free a stuck joint.
"Do not," he warned, "loosen the attachment points, because the mixer could become unstable, shearing the bolts and causing significant damage. Replace any check arms that can't be freed."
Wrap up your feed mixer's maintenance by checking the lights, reflectors and slow-moving vehicle (SMV) emblem.
Digman said, "Most states require that slow-moving vehicles - those traveling less than 25 miles per hour - be equipped with both SMV emblems and rear reflectors that are visible for at least 500 feet to the rear."