Weight or length
The main commercial indicator of pressed aluminum profile is its price per linear meter or price per kilogram. This price, of course, depend on the choice of alloy and the geometry of the cross section of the profile. In those countries, where active market mechanisms work, these prices do not differ too much from one manufacturer of aluminum profiles to another. These same market mechanisms are forcing aluminum profile manufacturers to constantly look for ways to increase productivity and reduce costs.. This allows them to lower the price of profiles and increase their sales..
Usually, the final price of aluminum profiles is agreed upon as a result of negotiations between the customer and supplier at the price of a batch of profiles, taking into account the complexity of the cross-section of the profile, special requirements for its functionality, as well as the level of profitability of a particular plant for the production of aluminum profiles.
Factors in the price of aluminum profiles
Important factors, which determine the production efficiency and the cost (and hence the price) of the pressed product - profile, tubes, bar or strip - are as follows:
- Profile length (whip, extrudate), which is pressed in one pressing cycle, that is, from one workpiece
- Extrudate End Length, which are cut into waste
- Number of measured profile lengths per workpiece
- Mass (weight) of the press residue
- Number and weight of spent blanks
- Weight (weight) of the order
- Press downtime between press cycles
- The speed of the ram
- Acceleration duration, that is, time, for which the full speed of the stamp is achieved
- Matrix Change Duration
- Blank price, spent on order fulfillment
- Matrix price
- Production costs
- Unexpected press stops
- Unexpected waste, that is, the number of profiles produced, which do not meet the specified requirements for their quality
Production costs are usually measured as the cost of one minute pressing. This cost includes all direct costs and labor costs of factory workers, which are divided by the time of the press in minutes.
Calculation of the price of an aluminum profile
Below is an example of a typical calculation of the cost of a meter or kilogram of extruded aluminum profile. We emphasize, that this is an example American (USA) and for the time before 2004 of the year. So, that you shouldn’t directly transfer it to our soil, but trace the logic of building the price of an aluminum profile, we think, It will be useful.
Basic initial data:
- Profile Cross Section – 437 mm2.
- The size of the measured length of the profile is 6 m.
- The number of profiles in the order - 200 pcs.
- Diameter of the press container - 178 mm.
1) First, calculate the mass (weight) of the feedstock - blanks.
Profiles are cut to measured lengths according to 6 m. From each blank you need to get, for example, 6 pcs. Moreover, the first and last meters of the lash (extrudate) are considered to be of poor quality and therefore discarded. The total length of the lash in one cycle should be:
6 x 6 + 2 = 38 m.
The mass per linear meter of the profile can be calculated from the cross-sectional area and density of the aluminum alloy:
0,437 x 10-3 x 2700 = 1,18 kg / m
According to the data obtained above, you can find the mass of the profile, which goes to the receiving table per piece:
1,18 x 38 = 44,84 kg
The length of the given initial blank should include a press residue of length, for example, 0,02 m. Since the diameter of the container is 178 mm, then the mass of the press residue will be:
3,14 x (0.178 / 2)2 x 0,02 x 2700 = 1,34 kg
The total weight of each piece will be:
44,84 + 1,34 = 46,18 m
In order to compensate for typical rejects from this plant, for example, 6 %, need to produce on 12 profile lengths longer, than indicated in the order, i.e 212 pcs. Then the number of required blanks is:
212/6 = 35,3.
Thus, To complete the order you must 36 workpieces total weight:
44,18 x 36 = 1614 kg
2) Total weight of profiles, which is delivered to the customer, However, is only:
1,18 x 6 x 200 = 1416 kg.
3) We obtain the yield by dividing the mass of the order by the mass of the original blanks:
1416/1614 = 0,877 = 87,7 %
4) Then we calculate the total spent production time.
Pressing speed - profile velocity at the exit from the matrix - for this particular alloy and the geometry of the cross section of the profile is, for example, 36 m / min or 0,6 m / s. Additional time, which is spent on acceleration of the press stamp is, for example, 7 from. Since the length of the profile per piece is known (38 m), the total time of one pressing cycle will be:
38/0,6 + 7 = 70 sec
Then you need to evaluate the downtime of the press between two press cycles. Time, press balances, loading of a new workpiece and air discharge from the container is usually about 15 seconds. If no other unforeseen press stops are expected, then you still need to add time, which is spent on changing the matrix. It may be, for example, 180 seconds.
Then the total production time of the press for pressing this order will be:
(70 + 15) x 36 + 180 = 3240 sec = 54 min = 0,9 h
5) Press productivity per net order quantity 200 six-meter profiles will be:
1416/0,9 = 1537 kg / h
6) Finally, you can calculate the cost per meter or kilogram of this aluminum profile.
For this, we also assume, what:
- The price of the workpiece material is, for example, 1,5 Doll. USA per kilogram.
- The production costs for this aluminum presser are, for example, 50 Doll. USA in one minute.
- The matrix price for this order was 2000 Doll. USA.
Then the total cost of making an order - taking into account the cost of the matrix and without - will be:
1,5 x 1614 + 50 x 54 = 5121 Doll. USA
5121 + 2000 = 7121 Doll. USA
Aluminum profile cost: per kilogram and per meter
As a result, the cost of a running meter of an aluminum profile is:
5121/1200 = 4,21 Doll. USA for 1 m
7121/1200 = 5,93 Doll. USA for 1 m
Accordingly, the cost of an aluminum profile per kilogram is:
5121/1416 = 3,62 USD for 1 kg
7121/1416 = 5,03 Doll. USA for 1 kg
Of course, the same matrix can be used for several orders. If the entire cost of the matrix is superimposed on the first order, then in the following orders its value is not added. Matrix maintenance costs are included in production costs..
From cost to price of aluminum profile
To the cost (cost) of the aluminum profile calculated in a similar way, the factory planners-businessmen will add their additives and the final price of the aluminum profile will be obtained.
The above simplified calculation of the cost of an aluminum profile is a purely American (USA) example. Therefore, the price of blanks, labor costs and final aluminum profile prices are also american, at what as somewhere before 2004 year. Some nuances of calculating the price of an aluminum profile are not shown in this example.. for instance, can not see, how were those "extra" taken into account 12 "Defective" profiles (6 %), who went, apparently, for remelting, and then returned to production in the form of new blanks. There are also other roughnesses - we give "as is".
Handbook of Metallurgical Process Design / ed. George E. Totten, Kiyoshi Funatani, Lin Xie / Marcel Dekker Inc, 2004