For those who have not yet used it - the principle of orbital grinding is not only the simple rotation of the working sole around its axis, but also the displacement of its orbit by 2-6 mm achieved by an ellipsoid eccentric. Than and the magnificent effect of abrasive grinding is reached.
Orbital grinding machines, like many other garage tools, come in a version with an electric motor or air driven by a compressor.
Usually, for routine garage work, mechanics use orbital machines with electric drive, as the pneumatic equipment requires high air consumption for its work, and, accordingly, a sufficiently powerful and large compressor.
A constantly running compressor puts pressure on the ears and silences the brain, so it just needs to be put in a separate room, which is not always possible in our garage case, and the power consumption is impressive. Therefore, a pneumatically driven tool, despite its low weight and some other advantages, is very appropriate in car workshops having a good power supply and where one huge compressor with the same huge receiver works for the entire car service. For this reason, we will not consider pneumatic orbital grinding machines, but look to the electrically driven orbits.
The main parameters for the selection of an electric orbital grinding machine:
Well, firstly, it is of course its power consumption (W);
Rotational speed and smooth adjustment of the rotational speed (r / min);
Oscillation frequency of the sole;
Change or inability to change the magnitude of the eccentric stroke (mm);
Diameter of the working sole (mm);
The presence and number of holes in the sole for the removal of dust;
And of course its weight (kg)
Equipment:
Usually, a hexagonal key for removing and installing the sole, a container or a bag for collecting dust is included in the orbital grinding machine, in some models there is an additional handle. Instead of a removable dust bag, you can connect a vacuum cleaner.
So, the first parameter is power.
In the main mass, orbital-grinding machines have a power consumption from 200 to 600W.
Accordingly, the greater the power of the machine, the better you can do the processing of the ground surface, regardless of the load placed on the sole of the orbital and the voltage drops in the network in your garage, but, on the other hand, it will be heavier in weight and price.
The second and third parameter is a smooth adjustment of the speed of rotation and the frequency of oscillation of the sole of the orbital grinding machine.
Typically, the speed of such machines is adjustable from 2,000 to 13,000 rpm, and the oscillation frequency can reach up to 24,000 count / min.
Note: This is the maximum speed (meaning idling speed without load) you will hardly need in the garage work to prepare the car for painting. Usually, 5-6 thousand turns are enough for the eyes. Therefore, buying an orbital machine, do not focus your attention on the maximum speed.
But it is very useful to have an electronic stabilization system of revolutions, as well as automatic soft start and brake, triggered when you press or release the power button. The presence of these electronic features will greatly enhance the quality of work.
The change in the magnitude of the eccentric stroke.
This possibility significantly increases the possibility of high-quality repair paintwork. Typically, the eccentric stroke ranges from 2 to 6 mm. The smaller the stroke of the eccentric (orbit of rotation), the more high-quality surface treatment, the less noticeable "curls" on the treated surface.
The more eccentric stroke, the rougher the processing and faster.
The ability to adjust the eccentric's stroke is present on orbitals from a non-cheap segment. But, the presence of such a convenient option does not always meet with automasters full approval. The fact is that many automasters prefer to have two orbital machines - one with an eccentric stroke of 5-6mm for working with a rough surface, such as sanding putty and primer (abrasive from P40 to P800) and the second, with a stroke of 2-3mm, for grinding varnish (Р1000-Р2000, as well as for “Abralon” and “Trisak” with abrasive Р2000-Р4000 - we kill shagreen leather and garbage on the varnish) under polishing.
Diameter of a working sole of the orbital grinding machine.
It is important, it is 125 mm and 150 mm. The choice, in one direction or another, should be made by examining your local market for consumables - for the presence of abrasive circles of the appropriate diameter. If this does not matter, then the choice in favor of 150 mm is unambiguous.
Number of holes in the sole for dust removal.
Different manufacturers of abrasive materials, such giants as Mika, 3M and many others produce abrasive cups for orbital machines in various versions - from 6 to a dozen and a half dozen holes for dust removal from the working surface. This is not a matter of principle, so this point can be missed.
Of course, it is good when the holes in the abrasive circles coincide with the holes in the sole of an orbital grinding machine.
But ... The Russian market is unpredictable and in our realities it is not always possible to buy what you need. Sellers buy in bulk those abrasive cups, which are currently cheaper or what is on the wholesale base, so it’s not important to focus on any particular type of holes.
Today it is 6 holes, and tomorrow, you will come to buy, and you will be offered abrasives for 9 holes, while others will be told, no!
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Thanks to every car-lover, who read this page till the end - I do honestly hope that this information helps you a little ! Come back as soon as possible. A lot of interesting things are coming soon.