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The first question we ask when optimizing your automatic sanding and grinding process is: What is a fixed fact in your situation (possibilities of the machine for example) and what are variables? That is the starting point with which we are going to achieve an optimal result. We measure that result in time, because that is the most expensive part in the whole process.

The most important question is: which sanding belt is going to make money for you?

With any tyre from expensive to cheap, you can generally reach the desired finish. But cheap and expensive are only relative concepts. The question is which sanding belt is going to make money for you. Because it reduces the number of steps in the process or it performs well at a higher throughput or has a long service life. All these points have the great advantage of saving time. And time is much more valuable than the purchase price of a sanding belt.

As a rule, the more pressure you can apply, the faster you can work.

The maximum pressure you can apply often determines how fast you can work. As a rule, the more pressure you can apply, the faster you can work. This is why the hardness and profile of a contact wheel in a broadband is also important. With a hard contact wheel you generate more pressure, just as with a wheel with grooves you generate more pressure by reducing the surface area of the contact point.

Below we mention four more parameters that influence your speed of grinding, each time the pressure is a determining factor. So always keep a close eye on this parameter, the influence on the other variables is enormous!

Three more parameters that are important for the removal speed of a grinding belt:

1. Tyre speed

If a sanding grain cuts easily through the metal, it takes relatively little time to do its job. The throughput speed can be increased so that work can be done faster.

Essential here is that the sanding grain is given enough pressure and has sufficient contact time with the metal to break out so that a new sharp edge is created and the belt can continue to perform. (Regeneration)

Tyre speed advice

                                          Calibration and heavy machining Polishing stones Finishing

Steel 30-36m/s 25-35m/s

Stainless steel 30-36m/s 25-35m/s

Nickel alloys 30-43m/s 25-35m/s

Aluminum 20-25m/s 20-25m/s

Titanium 14-17m/s 10-15m/s

2. Throughput speed (broadband) or power/step-over (long band)

The higher the feed rate, the faster the work is done. Here, too, there is sufficient contact time between abrasive and metal and the sanding mineral is given enough pressure to regenerate. Only then will a belt remain sharp. How quickly or easily a grain breaks out depends on the mineral. Each mineral has its unique properties. If the grain cannot break out, it will round off and start to vitrify. This makes the band worthless. Match grain and speed to each other.

3. Surface mounted sanding belt

Sanding belt with linen back

A sanding belt with a linen or polyester back has a longer life but is also more expensive than a belt with a paper back. You use a linen back if you have a lot of repetitive work. This results in even wear and tear and prevents rutting. You can use the tyre completely.

A linen back tears less quickly than a paper back. If you can give a lot of pressure, choose a band with a linen back and a ceramic grain. This works the fastest by far. Although the purchase price is higher, you will still save money with this tape.

Sanding belt with paper back

A sanding belt with a paper backing is often much cheaper and certainly has a raison d'être. You use this belt if you have many different products to work with. All these different models create a different wear pattern of the belt, resulting in an uneven grinding pattern. This is often undesirable, which is why tyres are sometimes replaced prematurely. Then it is nice that the tire is not very expensive.

If you are not able to give a lot of pressure in your situation, a paper tape with a simple Aluminium Oxide grain can be the best solution. In spite of the lower pressure, the grain breaks out well and performs well under the given conditions.

Mineral and particle size

In addition to the back of the band, the type of mineral and grain size also play an important role. Each mineral has a "sweet spot": the optimal conditions under which they perform as quickly as possible and for as long as possible. This sweet spot is determined by the pressure and by the type, shape and size of the grain.

Standby time

Standby time is also of great influence with these long and wide tyres because changing the tyres is often a time-consuming job and the production process is therefore interrupted. The fewer changes the better.

Other important factors

Heat input

The application of wide and long tyres is often on thin sheet material. What is important here is that not too much heat is injected to prevent the sheet from deforming. If the sheet becomes too hot there are several options, depending on your own situation you can make a choice from the various possibilities.

• Reduce the speed of the grinding belt or the throughput speed. This increases the moment of contact between the abrasive grain and the metal.
• Sharp grains cut more into the material than they rub and polish. They chip more and bring in less heat.
• This principle also applies to the difference between a coarse and a finer grain. A finer grain gives more friction and therefore also brings in more heat. After all, there are more contact points with a constant surface area.
• By playing with belt and throughput speed you have influence on the heat development.

With this article we hope to give you some insight into the factors that play a role in the operation of sanding belts and the optimisation of your sanding process. As you have already understood, there are no hard statements to make about which belt works best on which metal. The power of the machine plays a major role, the contact wheel, the material to be machined and the desired finish. In this blog it is impossible to go through all the scenarios. But we are happy to visit you to give you tailored advice.

Speed is the determining factor. With a calculation example we make this clear:

Costs machine + set up + belt + material consumption = € 150 per hour

By working 30% faster you save € 45 per hour which is € 360 per day.

Webinar on automatic deburring:

Watch our webinar that we made together with Q-fin. Grinding Power and the right consumables together ensure the optimal result. Which factors are important and how you can influence the final result, you will learn in this webinar.

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