What kinds of characteristics of a good cut-off wheel should have? We normally tell quality levels from these 2 main factors: cuts(life) and speed. Besides, some account these: consumption and cutting experience.
Well, in fact, it is more above way when we need to chose the right one from all brands disc. It happens one same metal cutting tools get different testing conclusions in different cutting test methods, which are related with the:
- Cutting object
- fix ways(cutting ways),
- machines to use (extracted Force)
I would like to introduce the main methods and the main comparing points we would think about when make final choice.
METHOD1: Automatically Comparing Cutting Test.
Someone think that the test result gets right only after taking human out of test process, set up anger grinder on the mechanic arms that move up and down in perfect vertical position, also, 3.1 ponds of downward force be extracted on grinder.
There are several things that going to be recorded:
- How much is cutting disc?
- How long does it take to cut through one piece of steel?
- Observe does the disc shatter?
- The diameter and weight consumption.
The main procedures:
We clamped 1/2” wide (thick) and 3” tall steel flat vertically and make sure the temperature of steel keep in around 73F.
The real diameter should be measured before setting up 4.5 inch cutting disc, then turning on the arm. The grinder will automatically move downward with 3.1 ponds force. After 1 cut we record: speed, diameter consumption and weight consumption. These data will be checked together with the sale price of disc in the market to select.
Comments:
We have to admit that considering the price and in avoid of human interruption in the process can make our selection is more nearing to real needs. Making the test relatively fair since all basically in the same condition.
However, In our practice: The technicians always be the one to operate instead of just machine. More our attention be attracted by the speed, despite there is a record of consumption. We barely cann’t tell the durability and efficient just through 1 cut.
For more information:
METHOD2: Different Material for Fixed Cuts.
Clients usually sent operators to process the test. The operators also be divided into two type-Skilled and experienced technician/ New worker with few experience.
The main procedures:
Measuring the real diameter of 4.5”cutting disc. Then manually cut on these 5 types of material:
- Angle steel 1”*0.125” thick
- Mild square tube 3/4”*0.062 thick
- Stainless steel Tube 1”*0.12”
- Galvanized Tube 0.085”*0.12”
- Steel flat 1”*1/4”
Using 3 pieces for 5 cuts per disc. Recording ending diameter/cutting speed of per cut.
Comments:
The cutting situation of test is the same with the normal practice. Multiple materials can indicate the application range of each disc, so we can know it’s strength and shortcomings.
The test only reflect the speed well, while for the overall cutting efficient and stability, I am afraid we cann‘t tell well from the test data. Usually any one of this 5 types material can stand up the quality level, so considering the testing cost we can get similar result by testing 10 pieces or 5pcs in one material.
For more information:
METHOD3: Third Party Test: Robotic Cutting.
To assure the least interruption as possible, clients can sent the samples to the third party. All the cutting test processed in fully automatic machine (Robotic testing).
The main procedures:
The 3 pieces 4.5” metal cutting disc cut on 1/2” rebar Rod on the platform with fix force 8+/-0.5 pounds extracted on 900W grinder. The whole process is in fully auto-control until the last cut. After cutting, there will be a performance test sheet to record:
- The total cuts the disc can get in all 3 times
- The speed for per cut
- Final stop cutting reason including: Wheel broke during cut or wheel too small to cut.
The other is consumption data sheet to record:
- Wheel wear in per cut
- Wheel weight wear in per cut.
Comments:
In this way, The consumption can tell us well the efficient the disc can get. The comments during in the test will suggest the strength of the best cutting disc for stainless steel but in too simply to show us the real cutting experience.
In real life we seldom use automatic machine process the small diameter cutting disc.
even with fix pound on grinder, there is always some little error in the force somehow, so we may can easily distinguish the disc that in huge quality gap, but hard to tell the disc in similar quality level.
For more information:
METHOD4: Speed Comparing Test and Life Comparing Test.
For the clients that take these two factors both matter, they will process the speed test and Life test on the two objects: ①Stainless steel plate size usually is 2″ tall, 1/4″ thick.② Mild carbon steel flat 2’’ x1/4’’.
The main procedures:
- The operator set up 1 piece 4.5 inch cutting disc on grinder in 900W or 1000W manually cutting on both materials until cann’t.
- Then we record the total cuts and the total time for all cuts to get the speed for per cut.
- Take out another piece on both materials too but to cut only 10 cuts then mainly record the time for each cut to get average time.
Comments:
As we can see this testing way focus on just two factors: Speed and Cuts (life). That will be also classic way and easier to process, also faster to get the outline of quality.
The final diameter would be determined by the operator, so it is better to choose more operators to join the test or take in the consumption into consideration.
METHOD4: Cutting Test on Angle Steel.
For this shape of object I decide to split it out,since the clamp way (cutting point) and cutting shape are different, which effect the performance comments.The two clamping ways seem A .Operators will get better cutting experience from the left one.
There are mainly two types of cutting test:
- Some apply grinder manually cutting on Angle Steel in size 1” x .125”(T) or 70mmx70mmx3mm. First we cut 15 cuts or 10 cuts even 50 cuts, then record the left diameter of the disc and the speed for each Cut, so we will get final Diameter and the speed to do comparing. You can cut one piece out or you also can just cut one side seem B. We should know how to put a cutting disc on an angle grinder.
- We just cut out the corner of Angle Steel, and we cut the disc completely done to see how any cuts it all can get. I believe you may notice that for this shape, even one same disc can get different performance if we cutting in different position or even size, so we should carefully to check all parts and that demands more professional operations.
All in all, we suggest that :
The tests should be processed according to the real life
You will doubt that if that will be too subjective. To lower down the effect of this part, it is better to chose at least 3 different operators to process the test. And choose best disc for grinding welds or metal.
For other parts we also should keep in the same situation :
- Are the grain cutting tool in the same or similar level and same application?
- Are the discs in the same date of production date.
- Make sure all disc in the same level and condition that is what we can control.
The size of object should suitable to the diameter of cutting disc
We seldom use small size like 5” cut-off wheel cutting on diameter over 20mm Round Bar, or over 60mm wide Angle steel. Because the large size cann’t hold many cuts (since small diameter)so it is not good to check the stability of disc.
There are 4 testing data that we might check all together with:
- Total cuts the disc can get.
- The speed for each cut.
- The consumption of the diameter, also the consumption for per cut. This is the point to avoid the subjective judge of stopping cutting.
- The price of the disc. This part is the point that easiest to be neglected. It is important to choose suitable steel cutting disc factory. You are just looking for the best not caring about cost, you could ignore this.
Other factors for comments of cutting experience including:
- Easy installation on grinder
- The pressure applied during manual cutting
- The temperature of the cutting blade when working (If that is over heated).
Final Thoughts
The right cutting wheel types that should be in good balance of life and speed, and good cutting efficiency, also in higher worth than the price. Smart choice should be made considering all the points instead of monitoring by one factor. That is all for today’s share and we are welcome to your any comments!