Ten defects affecting the procedure of knotting on the press machine.
1. Find the maximum basic information available about the press.
The indicator is the year of manufacture and the number of bales made. There are other requirements regarding the weight of bales before the year 2000 and in the contemporary era. The variant most frequently used by operators under the dimensions of 120 cm x 90 cm x 2400 cm is the weight of 400 to 600 kg per bale.
|Large square bale press market overview
|Year of manufacture
||2012 till today
|Weight of the bale
||less than 300 kgs
The rule of a lower weight of the bale does not pose as many requirements as to the quality of the string and the functionality of the knotters. There is also the choice of the pressed material - if we press the hay, the pressed mass should be more unobstructed and it is not necessary to squeeze it at the maximum, while the straw must always be pressed to the limit of the maximum pressure.
|TYPES OF STRINGS according to JUTA
||MASTER ORIGINAL 12kg
|Metres in 1 spool
|Weight of 1 spool
A bad choice very often results in a lack of node mechanism functionality. In any case, a combination of various types or string manufacturers is irrelevant on the same machine. Always adhere to the value recommendations according to the string strength indicated by the manufacturer. A simple tip in case of a problem: try to reduce the pressure to 50 %, use a lower grade of string and observe if there is a change.
2. Other necessary data that will give you the indication of the state of the press
How many bales has your press already made? Is there a pre-season review of your press or other form of periodic service?
|State and frequency of defects according to the number of bales and the age
||Need for service interventions or major repairs
|New machine → 15,000 bales / 1 -3 years of use
||without having to interfere with the functional binding
|15,001→ 30,000 bales / 3 and more years of operation
||pre-season inspection + watch for wear condition
|30,000 bales max. > 30.000 / multi-year operation
||mechanical damage wear on knotter parts again pre season inspections
|→ wrong setting / unprofessional intervention
||results in malfunction and high costs
3. The operation of the press machine within the row affects the final shape of bales:
3.1 bad guiding functions of the press → check the service settings (displayed on the terminal)
3.2 the operator does not respect the shape of the rows → according to the guidance (screen out of order or damaged)
3.3 the ideal shape of the row - ideal collection of small rows in a single large row using the central pick-up which forms the ideal uniform row
3.4 bad shape of the bale - the bale twists and ends up in the shape of a crescent - it happens to the string to break and as a result, all strings break in turn. Next, the mass of the bale breaks down.
Exceptionally, the strings break in one bale only! → Was the bale made a second time? / a disintegrated bullet → The problem is a high density of the weight of the bale - when the mass is pressed a second time, the compression of the mass is even greater and the string does not hold the high weight. After a few moments, there is tension and all the strings give way after the knot. The reason is, though almost unbelievable, the mass that has been pressed before, is further distended and the strength of the string no longer holds tight enough.
4. What about the occurrence of defects and their frequency?
The frequency of the occurrence? - all after the knot or before the knot
If it happens, under a daily performance of about 450 to 700 bales, less than 10 strings breaks, it is possible to consider this as a normal occurrence. It refers to the planned recharge of the coils and the binding. It depends on the type of manual nodes that the operator uses (if they are long enough close to completion). When a node degradation occurs, the operator has an electronic or mechanical signaling according to the comfort of the equipment of the press.
4.1 Is the problem already happening in box containers?
4.2 Do problems with knot formation or twine degradation happen somewhere between the replacement boxes through the rollers and the brakes to the knotter?
- pebble or small eye used to pass the string are worn → replace them
- poorly adjusted brake → adjust it (i.e. adjust it according to the others using a dynamometer to the value of those that work)
- damage by the roller (the pivot) if the roller does not rotate → an acute angle is created and deteriorates the string
- damage to the rollers directly on the pressing needles → also check to see if they rotate freely and are not damaged. If necessary, replace them with the new ones (which can be screws or rivets)
4.3. does the string frequently curl directly on the knotter?
4.4 the damage happens after the knot is made, i.e. after the knotter
4.5 in order to know where the damage may originate, it is necessary to inspect a bale already finished and expelled in order to be able to control the acute angles - on the frame of the machine through which the string passes in the rear part of the room on the ramp when the expulsion of the bale
5. Have one or more knotters stopped making knots?
5.1 Check the function of adjustment of a knotter
- Is the right type of string used? Or several types or a combination of several manufacturers?
(various colours x diameters) → check of the room containing strings
5.2 More than 3 → a service debug fault → return to point No. 2.
5.3 How many bales has the press made? Was there a knotter service intervention according to the manufacturer's instructions? For example, the recommendation of the service department of the Rasspe company is to control after reaching 10,000 bales. Or to check the basic adjustment according to the manufacturer.
6. The strings are the same but one or two knotters do not work
6.1 → checking the sharpness of knotters - the problem is the powdery environment and fouling with fine straw
Manufacturers install various types of knot grooming or cleaning mechanisms before the cycle
- using the air flowing through small tubes that end with a jet = the air stream just before another cycle of the knotter
- using electric fans, check if they are not dirty with straw or if they are functional at all
- another system depending on the manufacturer - or a combination of previous systems
6.2 check the ventilation system – 7 bars (3 bars is very little!). Connected to the tractor's air brake system. The problem is that inside the air tank, the air humidity causes corrosion and damage to the pressure regulator. It is good to purge the air tank of any water. In older tractors, there is often a problem with the compressor alone, which does not fill the circuit enough. To control the adjustment, in most cases it is possible to adjust the interval electronically (shortly and more frequently).
6.3 The problem with wheat is a high amount of dust in the presses that use an additional crusher – straw is crushed into small pieces, after which there is a high amount of dust and dust as well as remnants of the mass obstruct the entire press. The operator should, in the case of these machines, check more often the elements around the knotter → there is also a control of the sharpness of the needles of the lower part of the press in their lower position.
6.4 reduction of press pressure → the problem persists → a defect of the press of the hydraulic mechanism in the press (180 bar maximum for straw, 150 bar for hay). A common mistake of the operator is a wrong choice. Current new generations of presses are equipped with electronic pressure control, there is a possibility of pressing in a AUTOmatic way or according to instructions. AUTO mode starts to adjust the pressure quickly if the machine is handling wetter material. If the operator uses the MANUAL mode, the pressure reduction reacts very slowly or minimally. To judge the situation as best as possible, see the bale on the side where you can see equal layers. If they are not equal, this means the lack of proper operation of the press pressure regulation or the mechanical filling of the press chamber.
6.5 check of the condition of the knotter itself - when did the user replace (uncheck) the safety pins? For the anchorage pegs, there is a recommendation to replace them after 12,000 knots / bale, rather before reaching this number and in a specialized service at best (do not forget that it takes two knots per bale in the case of knotter double)
7. Checking the condition of the knotting machine’s apparatus itself
7.1 optical control of the knotter → pressure plate, point No. 4, spatula
- problem → the customer has used the knotter from another machine → it may well be an original component, but there was a different distance between the pegs → the roller - it cannot be replaced by itself → it must be possible to rotate freely → free movement check
- on the roller, NO surfaces or damages must be visible as these affect the functionality
7.2 check of the roller with lever to knives - also must be without visible degradation, it must be possible to turn it freely
→ control of the sharpness of the knife / rupture / damage
7.3 visual inspection of dismantling parts of the string holders - rotating rosettes with pressure spatula
- the wear of the spatule from the passage of the string and consequently a deteriorated functionality of the string holders during the knotting cycle
7.4 make a control adjustment - using physical force while staggering the clamps, find out how strong the resistance is and adjust according to what was found out
7.8 when necessary, make a control node manually – TEST
8. Extraordinary situations
Attention, it may even happen that a knot made manually arrives during the knotting in the knotter box at the same moment when it is hooked by a beak and during a partial turn, it is knotted on the knotter. It does not get loosened as it should, and the knot remains wrapped on the knotter. If the operator does not react, significant damage can occur during subsequent starts of the cycle.
9. Adjustment is to be done strictly according to the instructions of the manufacturer
9.1. If the user has multiple presses while using products from different knotter manufacturers Currently, there are two basic types of knotters available in the Deering system: the system is installed by Case, New Holland, Krone and Hesston press manufacturers. It is possible to distinguish them by means of the correct knot and small shortened pieces of the string:
a) Simple knot (made by the Rausendorf company) - the knot on the string is only made when the string moves up, at this moment the already pressed bale is knotted by a single knot. The weight of the bale 300 to 400 kg approximately.
b) Double knot (manufactured by Rasspe) - the basic difference from the previous system is that when it moves upwards, the needle ends the knot of the finished bale, but when it moves downward, it starts to start a knot for a new bale. We can see that a bale has two knots, which is required by the ability to squeeze the bale more densely and the resistance of the string. During the pressing process, one string at the top and one of bottom are added to the bale; both strings are linked to each other always at both ends. The weight of the bales is about 400 to 700 kgs, which means 270 kgs per square metre. Since 2013, some presses have been equipped with a new system of knotters and these reach up even to 800 kg. The mission of the needles is to pass the string to the knotters that are installed on the cylinder of the knotting mechanism.
9.2 The Cormick system differs considerably from the two previous systems and is used by the manufacturers of the Claas and Welger presses, it is a double loop node.
10. The mechanism of the knotter is naturally the most delicate part of the whole press, and therefore it is necessary to pay great attention to its service. It is still not a good rule to squeeze something firmly and think that the operation will be good. In practice, there is a problem that operators try to tighten everything firmly. It is better to think a little before doing and if you are not sure, study the instructions. It is also important to keep the user manual handy to make it easier for the operator.
10.1 If there is a situation with the shearing of the safety screws on the arm with the needles of knots, first, it is necessary to concentrate on the frequency of the phenomenon which helps a lot, however it always indicates that something is not working well and the operator should check the manufacturing development as soon as possible. If a safety screw has to be replaced, it is also necessary to replace its corresponding kits (this is not a rule for all manufacturers). Also a screw of the same firmness that is marked on his head (ideally an original piece of the manufacturer).
The frequency of bursting of the screw of safety of the knotting pins:
a) one to two times per season → was the check of the settings made before the season?
b) once or twice a week → make a check of the settings as soon as possible
c) several times a day → stop the operation of the machine immediately and check the settings
10.2 If the focus of the needle start does not match that of the pliers, it is better to seek the assistance of a qualified service. The basic rule for a knotter's needle is that they come out at the very moment the pliers are moving forward in view of the direction of movement of the tractor. In practice, it is possible to adjust this value to a bad moment, which ends up causing great damage to the machine since the needles remain at a bad time in the conduit and the pliers damage them when they push the mass in front of you. We strongly recommend having this intervention done by qualified personnel.