CHOOSING A BALANCING MACHINE

How to choose balancing machine correctly?

Make the right choice of balancing machine is a rather difficult task, considering their diversity, each machine has a unique design with its own characteristics.

To solve this problem, it is necessary to have certain technical knowledge in the field of balancing, for this reason we always recommend that customers consult with our specialists before buying, in order to understand some of the subtleties and nuances of the operation of various equipment.

What do you need to know to solve this problem? Let’s figure it out.

As you know, to solve a complex problem, it should be divided into several simple ones.

In our case we need:

1) Determine the needs of production.

2) Understand existing machine designs and their benefits.

How to determine your needs? It is not difficult, you just need to study the details with which we will work on the machine and take into account all the features of your production, and for this it is enough to answer the following questions:

• What is the mass, overall dimensions and design features of the parts to be balanced?
• What is the type of balancing rotors?
• What balancing tolerances do the products you will be working with have? So you should determine the minimum allowable residual imbalance according to  the State standard for all your parts
• What is the nature of your production? Do you manufacture products or do you only repair?
• Will parts of the same type be balanced or rotors of different designs?
• How many rotors will be balanced during one work shift?
• How well are the balanced products made? This refers to the quality of the supporting surfaces, are there any deviations in the geometry of the product, nicks on the base surfaces, are there any backlash or displacement of parts relative to the geometric axis if the product is an assembly unit, etc.
• Who will work on the machine? Age of a person, qualifications, are there any problems with vision, can he work with a computer?
• Under what conditions will the machine be used?

If you are ready to answer these questions, then I would recommend not to read further, but to call immediately to the sales manager and he will easily tell you which machine to choose. But if you want to understand the essence of the problem yourself, then go ahead.

Useful tips when choosing a balancing machine:

1. If your balanced rotor is in the form of a disc or drum with a hole fit:

Choose a machine with a vertical spindle

Such a part can be balanced on a universal machine with a mandrel. But the performance will be much lower. And this makes sense only for small-scale or repair production.We do not recommend choosing a machine with a horizontal spindle (with very rare exceptions).

The part must be installed directly on it, there is a high probability of balancing errors associated with the displacement of parts, since the mass of the part always tends to one side, in addition, there are difficulties with the correct installation of the rotor on the machine if it has a mass greater than you can lift with one hand .

2. If the geometry of the product is systematically violated due to warping of the metal after welding, a leash, etc.:

The machine should be selected in such a way that the weight of the product is in the middle of the load capacity of the machine, since there is a huge probability of a large initial unbalance.

Due to the appearance of a large initial imbalance for such products, it is recommended to choose a pre-resonance type machine, it will allow balancing at lower speeds. This will simplify and make the balancing process safer.

For parts like: pump disk, fan wheel, balancing system must necessarily have the function of decomposing the imbalance into static-torque components, since there are situations when it is enough to eliminate the static component of the imbalance and simply control the torque component.

When choosing a machine for such parts, it is necessary to take into account not only the mass of the balanced rotor, but also the weight of the mandrel that will be used for balancing.

Often, in pursuit of machine accuracy, the customer forgets about other important characteristics, for example, the maximum allowable initial unbalance, otherwise you will have a very accurate machine on which you cannot balance anything. For welded parts, the maximum unbalance that a machine can determine is more important than the accuracy of the tank, and its manufacturers never indicate in their offers, catalogues and websites.

3. If your rotor has large overall dimensions and/or the part has a complex design:

 

• Choose a machine that has roller cassettes high above the bed or belt drive and is height adjustable to ensure safe machine setup.
• Consider not only the width and height of the rollers, but also the roller cassette, as this is a common mistake when choosing a machine.
• The belt drive and supports must be able to move to any position relative to the bed during setup. Otherwise, you may be unable to install the product on the machine.
• The design of the supports and the belt drive should allow them to be installed almost tightly against each other.

 

4. If the rotor has a very large mass (the problem is pronounced on rotors over 3 tons and on rotors over 8 tons):

• For such parts, it is definitely better to use a over-resonant machine with self-aligning cassettes and cylindrical rollers (in our classification, these are machines of the 9K series)
• The rollers should be wide and have a cylindrical shape, since if the rotor bearing journals do not have sufficient hardness, there will be a high chance of “knurling” on them during the balancing process. This can cause damage to the rotor.
• Acceleration, deceleration and balancing time must be kept to a minimum to prevent the possibility of "knurling" on the rotor necks, so the large power of the electric motor and the presence of a frequency-controlled electric drive is an advantage when comparing two identical machines. Because on a machine with more power, the rotor will rotate less in time.
• The balancing system should start measurements when the rotor speed reaches 200 rpm, this will make the balancing process safe and also reduce the chances of “knurling” on the rotor necks.
• The design of the machine must have a device that allows for a smooth installation of the rotor, otherwise the contact surfaces of the rollers of the machine will quickly become unusable and the machine will lose accuracy.

5. If the rotor has a console type:

• The design of the machine must have back stops or a radial (reverse) roller cassette.These units prevent the rotor from tipping over during balancing and do not create balancing errors.
• The absence of the above assemblies is justified only if the mass of the rotor is so small that the balance is provided by the tension of the belt.

 

6. If high demands are placed on the rotor in terms of the minimum allowable residual unbalance:

• Machines of the resonant group have a higher sensitivity due to the design features of the support suspensions and vibration sensors.
• The presence of many adjustment nodes will allow for perfect debugging of equipment.
• Axial stops used to limit the axial displacement of the rotor should not create errors associated with the contact of the end face of the rotor and the stop. To do this, it is necessary that the design of the stop allows friction to be minimized.
• The balancing system must have the functions of vector averaging and taking into account the eccentricity of the tooling.

 

7. If your production is repair:

 

• Choose universal equipment, as the specifics of your work involves a large number of rotors of various designs, sizes and weights.
• When purchasing a machine, do not forget about the equipment, the more it is, the more functional the equipment will be.
• Combined machines, which have both a belt and an axial drive in their design, will allow you to balance any part, regardless of its configuration.
• If it is necessary to balance the rotor assembly with bearings, it is recommended to use cross-roller roller cassettes, this assembly will allow you to ignore errors associated with misalignment of the bearings, and will also reduce the installation time of the rotor on the machine.
• Among the machines produced by us for repair enterprises, the 9D series of machines is ideal

 

8. If you have high volume or mass production:

• A special machine will be more efficient, since you have a large serial production of products, that is, the machine will rarely be readjusted, and the requirements for rotor installation speed are very high.
• A special machine will cost slightly more than a serial machine, but it will be several times more productive.
• The balancing system must have a small measurement cycle and indicate the permissible value of the residual imbalance.
• The machine must have a tracking system, in this case, the time to determine the place to eliminate the imbalance will take only a few seconds.
• To ensure the continuity of the balancing operation and eliminate the errors associated with reinstalling the rotor, the machine must have an unbalance correction module. In this case, the imbalance will be eliminated directly on the balancing machine.

9. If the machine operator is an elderly person:

 

• The interface of the balancing system must be designed in such a way that even a person with poor eyesight could work at the machine.This is ensured by a large font of inscriptions, light indication of zones, etc. (Look at the dimensions of the interface labels).
• Controls of the balancing system and the machine should be intuitive for any person.

 

10. If you have unfavorable conditions on the site for the operation of high-precision balancing equipment:

 

• Under conditions of low temperatures, dusty premises and poor-quality power supply, the balancing system, made on the basis of microprocessor technology, will last longer.
• In the presence of increased vibration from nearby equipment (without foundation spokes), it will be more efficient to use an over-resonant type machine.
• The machine must have a high degree of noise immunity if it is installed close to power plants or power cables, this is more typical for the 9K series.

11. Security

• Does the machine have at least protective covers for rotating parts and warning stickers about dangers.
• Sometimes additional protections can be ordered as options. You can always check with the manager. Ask.
• In the modern world, in order to save money, manufacturers of balancing machines have begun to remove the brackets that protect against rotor overshoot, casings that cover open belt drives, and they may not even put an extra limit switch on the protective cover.
• Look at the photos on the websites of other manufacturers, when the cardan balancing machine does not have brackets from the cardan shaft protrusion - this is wrong. But such machines are on the market even from several manufacturers.
• When choosing a machine, pay attention to what is written in the machine's passport about the rules for safe work on it. Are all major hazards described in the manual.

WE NEVER SAVE ON THE SAFETY OF PEOPLE WORKING ON OUR MACHINES  I hope this information will help you to make the right choice of balancing machine. For more information, please contact us in any way convenient for you. MAIN THING: we have been making balancing machines for 47 years . And we know a lot about them. We know how to make accurate, fast, reliable balancing machines. Use our experience and our knowledge in the selection of equipment. Ask us and we will advise! This will save you money, effort and time.