01.06.2018
TTD-Tritan Heat Exchanger
Reduces machining time by 57 percent with 90 percent increased tool life
The use of a heat exchanger is worthwhile in many fields of applications – not only in domestic heating systems. Wherever heat is produced, it can be actively used by a heat exchanger. And this helps to save costs and conserve resources in the energy balance. In turn, with the TTD-Tritan, MAPAL has achieved a quantum leap in efficiency for machining heat exchangers.
Many versions of heat exchangers are used in different industries. They help to make use of previously unused heat that is produced in the production process. This report deals with recuperators, i.e. heat exchangers where two liquid or gaseous media at different temperatures are pumped in circuits separated from each other. A heat exchange takes place without mixing the media. This technology conserves resources, saves energy and consequently increases the overall efficiency of production.
Plate heat exchangers and bundle heat exchangers play a primary role within the recuperators.
Structurally bundle heat exchangers are usually made of metal and consist of a tube bundle that conducts a medium and a so-called orifice baffle with a front tube plate that a second medium flows through. The exact design concerning the exchange mechanisms, tolerances or operating parameters depends on the respective use of the heat exchanger.
Structurally bundle heat exchangers are usually made of metal and consist of a tube bundle that conducts a medium and a so-called orifice baffle with a front tube plate that a second medium flows through. The exact design concerning the exchange mechanisms, tolerances or operating parameters depends on the respective use of the heat exchanger.
Multitude of full boring operations
The tube bundle of a heat exchanger closes with a tube plate that features a number of bores depending on the size of the heat exchanger. To ensure that the medium does not escape at this component transition, high requirements are set at the bores with regard to position accuracy and size accuracy. Stefan Kühnle, Business Development Manager USA, reports on his experiences from the petrochemical industry: “In this sector in particular, heat exchangers have enormous dimensions. The tube plates often have several hundred bores that must be reliably and accurately machined while having long tool lives.
Three fluted TTD-Tritan for the application
The TTD-Tritan was tested by a customer in the USA and was impressive all along the line. The TTD-Tritan that came on the market as a replaceable head version in 2016, was the only drill with three cutting edges that was available as a replaceable head system at the time.
Replaceable head systems in machining manufacture are first choice when it comes to meeting the demands of rising raw material prices, resource efficiency and streamlining of stocks. On the TTD-Tritan, tool head and tool holder are joined by Hirth serrations. This connection is easy to operate and particularly stable so that all the benefits and the performance level of the solid
carbide equivalent are fully retained with the replaceable head variant. In addition it guarantees optimum torque transmission with at the same time high changing and radial run-out accuracy. The TTD-Tritan is perfectly centred via its pronounced drill tip and ensures very good circularity – and that at lower costs, because with the replaceable head system, the cost-intensive carbide is limited to the tool head.
carbide equivalent are fully retained with the replaceable head variant. In addition it guarantees optimum torque transmission with at the same time high changing and radial run-out accuracy. The TTD-Tritan is perfectly centred via its pronounced drill tip and ensures very good circularity – and that at lower costs, because with the replaceable head system, the cost-intensive carbide is limited to the tool head.
“There were several reasons why we immediately decided to use the TTD-Tritan”, reports Stefan Kühnle. “For machining different versions of tube plates, the customer first needs every diameter version in several lengths. Here we are able to provide a very wide diameter range in all the necessary lengths with our consistent program. We can also use smaller diameters in
the monolithic solid carbide design. In addition less storage space is necessary when the wear parts are mainly limited to the drill heads. As a result the capital tied up in stock is naturally reduced. And finally we achieve significantly better cost-per-part values within the diameter range from 19 mm.”
the monolithic solid carbide design. In addition less storage space is necessary when the wear parts are mainly limited to the drill heads. As a result the capital tied up in stock is naturally reduced. And finally we achieve significantly better cost-per-part values within the diameter range from 19 mm.”
Bearbeitungszeit um 57 Prozent reduziert – 90 Prozent längere Standzeit
Die ersten Praxistests mit dem TTD-Tritan beeindrucken. Der Kunde bearbeitet Rohrplatten aus Kohlenstoffstahl SA-516-70N auf einem QuickMill Intimidator 120 Bearbeitungszentrum. Der Bohrungsdurchmesser liegt bei 1,008 Inch (25,6 mm) und die Bohrungslänge bei 2,5 Inch (63,5 mm). Dabei arbeitet der TTD-Tritan mit einer um 59 Prozent höheren Vorschubgeschwindigkeit als der bis dato eingesetzte, zweischneidige Wechselkopfbohrer eines Mitbewerbers.
Der TTD-Tritan erreicht einen Standweg von gut 53 Metern, der zuvor eingesetzte Bohrer dagegen nur 28 Meter. Zu dieser Steigerung von 90 Prozent kommt ein signifikanter Vorteil in der Bearbeitungszeit: Das MAPAL Werkzeug führt die Vollbohroperation in einem Arbeitsgang durch und benötigt nur 29 Minuten für alle 550 Bohrungen. Die Bearbeitungszeit wurde so mehr als halbiert.
Garantierte Verfügbarkeit
„Speziell bei der Bearbeitung von Wärmetauschern legen Kunden größten Wert auf eine garantierte Werkzeugverfügbarkeit“, unterstreicht Stefan Kühnle. Mit dem Werkzeugausgabesystem UNIBASE-M und den damit verbundenen digitalen Serviceleistungen können die Anwender sich zu jeder Zeit und völlig transparent auf die Verfügbarkeit der Werkzeuge verlassen. So ist die Bearbeitung der Rohrbündel eine Erfolgsgeschichte für Anwender und Werkzeughersteller.
