SUMMARY

First work, within a series of them, for productivity improvements. This deals with the case of a small line for sausage packaging.

INTRODUCTION

The search for continuous improvement of productivity is a must in every industry. We start with this work a series of them, in which we will develop various ideas in order to improve this productivity in small packaging manufacturing facilities.

Normally large manufacturing line installations are designed by specialized firms and their design is usually not easy to improve by the company that has purchased them. On the contrary, small installations for marginal productions, but which are sometimes the most profitable, are commonly made by the metalworker, using recovery equipment. It is in this field where the most inventiveness develops.

With these works we want to help in that sense, exposing achievements that are supported by practice.

PACKAGING IN SMALL LINES OF SAUSED PACKAGING

Sometimes small lines of presses are used for the manufacture of low consumption sausage containers. They usually use a packing system in boxes or bags, and it is done by taking the containers from a conveyor at the exit of the second cutting press. Let’s take a concrete example:

Line formed by:

–          Manual press of 1st operation prepared for drawing, in horizontal position with vertical feeding of strips. This feeding system is very comfortable, since it is limited to hand-drop the tin strip on the vertical entrance guide. In the work “Vertical feeding in presses of embutición” we will indicate how to do it

–          Magnetic lift

–          Manual press of 2nd operation to trim the excess material and equalize the flange of the container

–          Packing conveyor with 2 auxiliary tables for the simultaneous filling of two boxes or bags.

–          Utillada to manufacture sausage containers, for example 99 x 46

–        –          Average real speed: 40 to 50 containers / ml. Instantaneous theoretical speed: 50 to 60 in / mi

The direct labor necessary to operate it would be:

–          A person for the supply of metal strips in 1st operation. He takes them from an auxiliary table and deposits them in the vertical feeding guide.

–          Two people in the packing area to prepare boxes or bags, fill them and close them.

See figure # 1:

Figure nº 1: Small line for sausage packaging

 The productivity of the installation can be optimized in several ways:

•  A) Improvement in the packing station

Reduction of a person in the packaging packaging operation. It would be enough to significantly increase the storage capacity of the exit conveyor of the second press, so that it serves as a reserve while the person prepares the empty box or bag and changes and closes the full one. In this way, only one person is enough to serve the packing area. To do this, a fairly long and wide conveyor must be prepared. Its width must match that of the box or bag, so that the quincunx of packaging, if round, that is formed on the conveyor is the same as that of the box. Figure 2 shows the modified line.

Figure nº 2: Modified line with enlargement of the packing conveyor

 This conveyor can work well with a width of 60 to 70 cms. and a length of 7 to 8 meters.

You can still improve the task of the operator by providing a special clamp .. With it the rows of cans at the end of the conveyor will be collected and introduced into the bags. An example of this clamp is shown in figure # 3

Figure nº 3: Example of collection forceps of packages in packaging conveyor

 The use of it is done according to figure 4

Figure nº 4: Handling the packing clamp

Under these conditions, the price of the conveyor and the clamp will be amortized with the manufacture of 2 to 3 million containers.

•  B)  Location in the shape of “U”

Reduction of two people performing a “U” installation. For this we would need to have an automatic press to perform the first operation. It is possible to find a second hand at a good price with a low investment. It must have a suitable stroke crankshaft for embedded packings, a pneumatic cushion or a lower pressure system sufficient for this purpose and a store of bands of certain capacity. Maybe we have some in the warehouse of machines out of use. With good maintenance we will have it ready. The main problem may come because its speed is excessive. In this case we would be forced to change the transmission ratio of the crankshaft motor-drive pulleys. With this we would lose power, but it can be compensated in part by increasing the weight of the steering wheel

With a distribution of equipment as indicated in figure No. 5, one person would be enough to feed the press warehouse and roll up the packaging in the same conditions as in case A)

Figure nº 5: Location in “U” of sausage line

 Another variant of this option, would be to increase the speed of the installation, maintaining the one of the automatic press of 1st operation but increasing the speed of the second press. In this case, two jobs would be maintained, one in the packaging and one in support of the previous one and press feed 1 Op. The increase in productivity would come through the increase in speed.

•  C)  Automatic packing

The optimal solution would be to substitute manual palletizing in solution B) with an automatic palletizer, and go at the maximum speed allowed by the different machines. One person would operate the entire line. In this case the investment increases considerably and its amortization worsens, provided that we are moving in the field of small markets.