Product category:
Sawing and cutting-off machines and automation systems
News Release from: Kasto | Subject: KASTOtec-series high-speed saws
Edited by the Manufacturingtalk Editorial
Team on 06 May 2005
Productivity - it is about cutting and
idle times
High-speed-cutting is a proven method to achieve with high cutting speeds a surface finish of excellent quality combined with high accuracies - described here by Dr Fritz Heydt.
The initials 'KPS' means at Kasto the consistent performance increase when sawing: KASTOPowerSawing Innovation and systematic development of bandsaws as well as circular saws allowed Kasto to make technology jumps that set trends in the sawing industry
This article was originally published on Manufacturingtalk on 23 May 2001 at 8.00am (UK)
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What does KASTOPowerSawing mean? High-speed cutting (HSC) is a proven method to achieve with high cutting speeds a surface finish of excellent quality combined with high accuracies.
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High-performance cutting (HPC) is much closer to the cutting process since - by using carbide blades - the feed per tooth fz, and, dependent on that the cutting forces Fz and with that the cutting volume Qw or the cutting performance by definition increase very much.
This also requires the appropriate stronger drive capacity.
Related to cutting, this means, where high cutting performances have to be achieved, the performance at the saw shaft is most important.
High-performance cutting is herewith defined as machining with high tooth feeds and cutting speeds, which are almost doubled compared to conventional saws.
Can this high demand be proven with Kasto saws? In the following, we will try to give an answer for the methods bandsaw cutting and circular saw cutting according to the development in the last five years.
* It is all about cutting times and idle times - as we know, the cycle time for a saw cut is a combination of cutting or main times as well as idle times.
With the development of the carbide saw blade, the cutting time of the bandsaw could be considerably reduced.
But to make that possible, the bandsaws had to be designed to utilise carbide blades, which, according to the definition of HPC, require a rigid saw frame combined with good dampening characteristics, a higher drive capacity and the respective drive design as well as a constant feed per tooth, protection of teeth when blade is retracted and sufficient chip discharge.
This was achieved with the KASTOtec-series.
Due to years of experience, the saw unit is designed as a mineral cast composite construction.
An improved dynamic machine function achieves a much quieter operation, better cutting performances and longer blade life.
Extensive tests - and not only on saws but also on other machine tools - prove that the very expensive mineral cast has a six to eight times better vibration dampening compared to cast iron.
An advantage for the stability of the saw unit is also the robust, both-sided bearing of the bandwheels and the precise two column guides of the saw unit with modern linear guide systems.
As comparison material, C45 with a diameter of 200mm was selected.
With the previous model, the bandsaw Kasto HBA 420 AU, the total cycle time of 2.87 minutes was divided into a cutting time of 2,46 min.
and an idle time of 0,41 min.
Today's model, the KASTOtec AC4, needs 1,61 min for this task, which is more than 40% faster; the cutting time decreased by approx 40% and the idle time by approx.
90%.
Reasons are the higher cutting performance by using carbide saw blades as well as a consistent reduction of the substantial idle times by moving the saw head faster, by increasing the speed of the clamping jaws or speeding up the material feed rate.
Another result of the power saw development is that even difficult to cut materials up to a tensile strength of 18,000dN/mm2 or more - depending upon the material - can be cut with this machine without any problems.
Just a few years ago, such materials could not be cut.
* Production circular saws - strong in a little package - because of a different technology, the circular saw has a 10 times higher feed per tooth rate.
Therefore, the ratio of cutting times to idle times is different than with the bandsaw when using the same C 45 material with a diameter of 50mm.
A PKS 140 has with a cycle time of 0,49 min an actual cutting time of 0,21 min.
and idle times of 0,28 min.
Everything goes faster with the KASTOvariospeed: With a cycle time of 0,28 min, the main time decreases by 60%, the idle time by 25%.
The machine was also consistently designed for the use of carbide blades to meet the requirements of KASTOPowerSawing.
The technical basis for high cutting speeds and good blade life is the heavy-duty construction of the machine base and the use of modern machine elements.
The 18kW strong, frequency-controlled 3 phase motor - combined with a precisioin spur gear drive - powers either HSS or modern carbide thin-cut throw-away blades.
The last mentioned only produce a kerf width of 2.7mm.
The cutting range is for both tool types max 140mm.
A rigid, adjustable cutting feed, obtained via a pretensioned ball lead screw - is important for good cutting results with the KASTOvariospeed C 14.
Besides a patented blade guide, stronger drives, saw blades that are especially fine-tuned for the sawing task as well as reduced feed times for saw and material help to increase the performance.
Important are also fast material change times.
Magazine solutions offer a large supply of material on the infeed side.
Alternatively, material can be fed directly to the KASTOvariospeed C 14 from a AS/RS bar storage system or out of a cassette.
* Unitary approach of all parameters - comparing the two cutting methods, it is very clear that - besides the expected shorter cycle time with circular cutting - the ratio of main to idle times is very different.
These differences are due to the different sawing methods.
Therefore, it would we wrong to only optimize the cutting time for the bandsaw and the idle time for the circular saw.
Of course, there are promising approaches.
But the objective must be to continually improve all parameters that are important for the cutting process.
* Environmental safety as a side effect - another essential objective regarding KPS - that is not part of the cutting time - is the environmental safety.
When cutting with carbide blades, flood coolant is more and more replaced with a minimum amount lubrication or no coolant/lubrication at all.
This is an extremely important component with HPC, which is more and more the case with cutting.
* Summary - due to the evident progress in the development of saws and in cutting tools, one can say in conclusion that the Kasto production saws for sure fulfill the objective to reduce main and idle times considerably.
Therefore, KASTOPowerSawing is not a catchword but already reality in high-performance sawing.
This makes the use of high-quality and therefore more expensive equipment a necessity, which can be easily justified when applied to the right task by reducing the cost per cut considerably.
This is especially advantageous with integration into highly automated systems such as sawing centers with integrated storage where - due to clearly higher outputs and very long and unmanned machine cycle times- the total profitability of the system, when taking the overall cost under consideration, can be easily demonstrated.
*Dr Fritz Heydt is with Kasto Maschinenbau, Germany.
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