TPT May 2007

Now it is clear, that from the point of view of A), its increase in profit is almost negligible when compared with B). From the economical point of view, dividing by shear is definitely more profitable, in this case by €235,000/year. Therefore, calculations can be made regarding the payback period on investment in case of installing a flying shear cutoff machine Alda 76 X 3 – 100.

› Figure 3 : Flying saw cutoff Alda s 76x3.4-100, with AUT 7000 bundling machine shown in the background

The total saving per year is:

A + B + C + D = 34,000 + 21,000 + 4,500 + 235,000 = €294,500/ year.

The current costs of disposing of the solid saw waste are €0.4/kg. Thus, to dispose of the 6,500kg of waste costs €2,600 per year. Waste from a shear cut is solid and can be sold for €0.1/kg. Therefore by using this technology, instead of the assumed costs of waste removal, a profit of €1,950/year can be achieved.

Investment in buying the machine: Investment in buying the necessary tools: Installation and the original set up:

€150,000 €15,000 €173,000 €294,500 €8,000

Total costs :

Yearly savings:

Thus the return is 173,000: 294,000 = 0.6 year

The overall benefit to the producer is €4,560 per year.

D) Increase in production as a result of using shear cutoff

The return on investment based on the above analysis is just 0.6 a year (8 months), without even evaluating the additional positive effects on hygiene of work, ecology and internal costs. Please note: All the above data has been compiled from information offered by companies Attl a spol sro, JAKL Karvina as, Steel Profil sro and Ocelprofil sro. Recommendations for both dividing technologies for tube/profiles by flying cutoff After twelve years of experience in this field, the findings can be used to recommend an optimum type of dividing tubes and profiles with respect to the types of profiles and tubes, the maximum possible capacity of a production mill and the quality of the cut face required. We have divided the choice of machines produced by the Attl a spol sro into five groups as follows:

Additional savings result from the increased production as shown by the following two examples. Let us assume an annual production of 26,000t/year. Analysis of production data shows an increase in production when using shear cutoff by 43 hours, as a result of shorter necessary stoppages for cutting tool maintenance. 42 x 60 = (2,580min) x (60m/min) x (2.8kg/bm) = 154,800kg/year. Assuming a profit of €0.06/kg, increase of profit per year is €10,000. It can therefore be assumed, and actual production experience confirms this, that a forming line producing a profile 60 x 40 x 3mm will increase productivity by 20-30 per cent (assuming sufficient HF welder capacity) when the mill speed increases (graph 2). Using the assumed production of 26,000t/year the increase in speed will bring approximately 6,500t more production. At the above profit of €0.06/kg, using shear cutoff instead of a cold saw, will result in extra profit of €390,000 per year. If this theoretical profit is reduced by a coefficient of 0.6 to accommodate a realistic assortment of other profiles, it results in an extra profit of €235,000. Increase of profit as a result of less stoppages per year:

Flying cold saw Alda s 38 x 2.5 -140

Parameters

Values

Units

Tube diameter max/min Square profile max Rectangle profile max Wall thickness max/min

38/10

mm mm mm mm

30 x 30 50 x 10

2.5 ÷ 0.8

Material

S 185; S 235 JRH; S 235 JR; 1.4301; 1.4571

Graph 2

Mill speed max

140 (160)

m/min

Rotary saw diameter

400

mm

Number of cutting cycles for L= 6m

22

1/ min

Life of rotary blade between sharpening (est)

100 ÷ 160

t

Power input

120

kW

Comments: This is a proven type of flying cold saw with extra high rigidity of the saw unit and proportional control of feed motion by hydraulic cylinder. Using this saw for cutting the above small diameters does not offer substantial economic benefits.

157

M ay /J une 2007