Strictly-Extrusion

Steinfurt, 5^th October 2009: Material savings, reduced use of energy and higher quality are the central requirements in pipe extrusion. According to the most recent experience of Skoplast in Odolanow Kaczory (Poland) the 3LRK-extrusion head, made to the Lichter principle, opens up new dimensions especially in the area of multilayer pipe extrusion: obvious material savings, increase of the availability by process security and reduction of energy use, proportional to the savings on raw material. Altogether this means: substantially more pipes can be produced against equal costs.

The efficiency increase in the multilayer pipe extrusion is achieved by the perfect match of modern high capacity extruders, the 3LRK-pipe head and downstream equipment that meets the needs. The main scope at Skoplast is the exchange of their present feed block technology that has been used since 2000, with the Lichter head. Krzysztof Szkopek, one of the owners of Skoplast, now replaces the pipe head in a co-extrusion system to improve the quality and the profit. For the future this investment means being prepared for the planned change to Pb-free stabilisators.

Investment in profit

The Lichter head (3LRK-pipe head) is available in three sizes:

1. 3LRK-1 (50-100 mm)

2. 3LRK-2 (100-200 mm)

3. 3LRK-3 (200-400 mm)

For diameters above 400 mm the 3LRK-3 can be used with an extension module. The 3LRK in general is suitable for the production spectrum of smooth multilayer pipes in PVC, PVC-U, PE and PP. Thereby the core layer can be of recyclates, foamed recyclates, new material and foamed new material. The well considered principle of construction enables the operation without extra effort with two co-extruders, without extra effort, if separate colours and/or raw material-types are used. “According to our experience, the use of this Lichter head pays out for all new and replacement investments worthwhile according to our experience. Old extrusion lines become more efficient and with new production lines the end result will be improved”, says Krzysztof Szkopek. At the same time the total investment for a line with 3LRK-pipe head against a conventional pipe extrusion line with feed blocks is very competitive. Krzysztof Szkopek has been motivated for this investment of the till then far higher use of raw material and the clear improvement of quality: “we find a return on investment of widely within 6 months realistic.” Szkopek chooses the process technical support: support with commissioning and quality insurance is an integral part of the spectrum that Lichter extrusion technique offer Skoplast. The multilayer pipe head 3LRK therefore secures competitiveness of the Polish pipe producer.

Optimal melting diffusion

To guarantee an optimal melting diffusion the 3LRK-pipe head according to the Lichter principle has been based on a spike die. For PVC and PVC-U this is the almost ideal principle of construction, because the melt flow is delivered by the extruder into a circular shaped flow channel by the extruder. For the core layer, it is transformed by the mandrel directly into a coaxial spine flow. The melt of the outer layer passes through especially geometric formed channels into a relief zone that reduces material deformation and flows eventually to the exit nozzle. Additionally, the 3 LRK features a large inner diameter for the material stream. This construction results in a clearly more constant flow of the melt, thin and constant outer layer and dispersing of rheologic and viscosity differences in the layers.

Reduction in density in the total density with the 3LRK

For a model calculation of a SN4-multiple layer pipe (160 mm diameter) Lichter gives an output capacity of 450 kg/h as basic fact. With a total density of 1, 16 g/cm3 an output quantity of 4.476 m/day is achieved with conventional pipe heads (feed blocks). The 3LRK-pipehead allows for a total density of 0, 83 g/cm3 due to its construction and

special process measurements – the pipe is based on the physical weight now lighter than water. The output capacity with the same material input increases to 6.234 m/day, which gives an economical increase of 39%. This result becomes possible by two facts:

• More consistent outer layers because of improved melting diffusion
• Less density of the inner layer because of the optimal form of the flow channels, the recipe and the process technology applied.

The result is convincing because of material saving and a real quality improvement.

Energy saving and maintainability friendliness become more important

An equally important advantage of the 3LRK, in times of increasing energy costs, are large potential savings on the energy used for production and its compact dimensions. Conventional feed blocks are obviously larger and use up to 3 times more energy during heating up. The main saving would lie in the energetically better use of the applied energy in the extruder: it can deliver more pipes with the same energy use. According to Krzysztof Szkopek the pipe heads are more than anything friendly in maintenance and service: “the 3LRK has been built in sections, i.e. discs. This form of construction does not only enable a constant flow diffusion – it is more than anything maintenance friendly. Anyway we calculate with approx. 2 – 3 stops per year for cleaning the flow channels, because of particle contamination in the melt and other effects. With the 3LRK the restarting of production goes much faster than with a feed block. Moderate use of chalk as preventive measurement and increase of the E-module for the outer layer reduces these cleansing intervals. On the other hand in the foam layer we should take in account the higher density of the chalk. With production interruptions during the weekend or with change of dimensions the installation is easy to “freeze” and restart. This too reduces production costs and increases the use of the production installation.

Efficient and effective measurement of the wall thickness

The steady optimizing of the use of material is a distinguishing factor for a strong economic use in the production of multilayer pipes. In practice it is still common use to measure the average wall thickness. If one leaves out the eccentricity here, then this leads to an impressive more use of material, with drastic effects on the economics. An economic production of extrudates without the well suited measurement and control technique is practically unthought-of. For an exact determination of the layer thickness a measurement and control system is used in order to capture the layer thickness in many steps as well as to measure the layer volume. This method simplifies an optimal production process. In order to measure the pipes in an objective way Lichter has a special measurement system available, with which the layer thickness and surface volume of the separate layers over the total circumference of the pipe will be measured. These measurements can be weighed in a complex calculation and the results of single actions can be predicted by way of calculation. Based on the calculated value the recipe and extrusion line can be set in an optimal way. This also adds to an optimal cost saving combined with constant quality criteria.

(Pawcatuck, Conn.)-The home improvement products’ business for Jifram Extrusions, Inc. has been so good that the company purchased a Davis-Standard Super Blue® extruder with DS-eTPC controls directly off the show floor at NPE. The new 3 1/2-inch (90mm) extruder, installed immediately after the show, is being used to manufacture a range of products including closet organizers, storage solutions and fence covers. Jifram appreciates the quick installation of the Super Blue as well as the efficiency of the DS-eTPC, which includes a 12.1-inch (300mm) color touch-screen with built-in PLC processor and multi-loop temperature control. The DS-eTPC is Davis-Standard’s most recent discrete controller replacement.

“The training time for the TPC controller was minimal and the extruder was up and running in no time at all,” said Steven Fischer, President of Jifram Custom Extrusions. “The PLC decreased set up time and increased accuracy in setting the machine parameters on the TPC. We have not accessed all of the features on the TPC, but as we become more familiar with this machine, we are certain it will offer us even more conveniences.”

Jifram, based in Sheboygan Falls, Wisconsin, has been a Davis-Standard customer since the company opened its doors in 1981. After an initial Davis-Standard purchase, Jifram added extruders from other manufacturers, but realized the importance of purchasing from one primary manufacturer and went back to Davis-Standard. The company now owns eight Davis-Standard extruders and coextruders ranging in size from 2 to 3 ½ inches (50 to 90mm).

“We appreciate that Davis-Standard supplies high quality, durable, American-made extruders,” said Fischer. “They have an excellent reputation and very responsive customer service. We are a custom operation so we need machines that run a variety of resins at rates ranging from 1 ½ feet (.45 meters) per minute all the way up to 150 feet (45 meters) per minute. Davis-Standard has also helped us with our coextrusion and triextrusion capabilities.”

While the company’s home improvement business is growing, Jifram’s primary specialty is the point of purchase market. Jifram products are used in displays at major retail outlets throughout the United States. They also supply to OEM customers, two of which were Jifram’s first and second accounts when the business first opened. Jifram does most of its business in the Midwestern part of the U.S., but has also shipped to Canada, Mexico and Taiwan.

According to Fischer, Jifram’s greatest advantage is its people. Jifram is a family owned and operated business. The company’s founder James R. Fischer (Steven’s father) is still active in the business. Employee turnover is minimal. The company’s first hired employee is still there, working as Jifram’s Quality Control Manager. Steven and his brother Greg learned the business early, both helping their father as teenagers and coming back to the business full-time after college.

“Being a family owned business definitely impacts how we operate. We are focused on customer service, ingenuity, competitive pricing and lead-time. We realize that we can no longer just extrude profiles, we must be a full service company,” explained Fischer. “Davis-Standard has played an important role in supplying the equipment needed to support our evolving business model.”

For more information about Jifram, visit www.jifram.com. For more information about Davis-Standard’s Super Blue extruder and DS-eTPC controllers, contact Wendell Whipple at [email protected].