Starrag and KOSO Kent Introl use their heads to open the floodgates to single set-up valve savings
KOSO Kent Introl’s latest investment in the Starrag Group’s Heckert 630 DBF horizontal machining center is paying big dividends in the machining of valve bodies, not least because the machine’s ability for single set-up, multi-tasking machining – milling, turning and drilling – has eliminated the need for two separate machines, and all the associated re-setting and queuing times, to produce finished workpieces.
The success of the DBF machine builds on the prowess of the company’s other Starrag brand machines – in particular, a Scharmann Ecoforce HT2 with integrated P600 facing head that has consistently and reliably proved its worth in the single set-up machining (milling, boring and turning) of larger workpieces at the company’s Brighouse (West Yorkshire) site.
And the Heckert DBF’s record in increasing KOSO Kent Introl’s machining capacity of smaller valve and globe bodies, and its ability to effectively transform the production process for such parts, is now similarly attracting acclaim.
Separate turning and drilling
We were previously using two machines to complete the bodies,” continues Mr Addy. “A lathe to produce the flange and plug-way in three operations; then the part had to often queue for a separate operation (and additional set-up) on a drill, the final operation.
“In needing to increase capacity, and with a good working relationship with Starrag, we had no hesitation in selecting the Heckert 630 DBF which offers a machining capability and specification that more than meets our needs for valve body machining: 24.8 – 24.8 in pallets: X-, Y- and Z-axis travels of 42.13 in, 34.25 in and 47.24 in, respectively, and traverse speeds of 1,574, 1,574, 2,362 ipm in X, Y and Z; plus +/- 1.38 in in the U (turning) axis; a 60.35 hp / 1,254 ft / lbf spindle.
“The DBF machine enables the production of complete body machining in one or two operations, depending on casting type and size,” says Mr Addy. The DBF strategy – for angle bodies in one-hit and for globe bodies in two operations of set-up for machining the plug-way (including drilling) then set-up and machine the flanges (including drilling) – has replaced a comparatively longer and laborious process of:
- Load to lathe
- Set-up and machine first flange
- Set-up and machine second flange
- Set-up and machine the plug-way
- Move body to drilling cell
- Set-up and drill
Established record of success
KOSO Kent Introl’s company’s association with Starrag stretches back over many years; indeed, its heavy machine shop exclusively features Starrag brand machines – a Solon 4 machining center and a Dörries vertical turning lathe plus the Scharmann Ecoforce HT2 machining center equipped with integrated P600 facing head.
With X, Y and Z axes capacities of 78.74 / 98.43 in by 62.99 / 137.8 in by 86.61/143.7 in, respectively, and able to accommodate workpieces of 22,046 lb, the Ecoforce not only offers the capacity for the company’s larger workpieces but also the power – a main spindle rated at up to 84.48 hp spindle that produces 2,950 ft / lbf of torque for even the heaviest of milling and boring cuts, and the facing head for in-process turning at up 300 rpm.
“We’ve proven the reliability and consistently high-quality machining results from our Starrag machines and, coupled with the fact that we’ve always received excellent after-market back-up and support from the company, it made complete sense to continue that single-source association when we needed to address the throughput needs of our smaller valve bodies,” says Mr Addy.
“We also knew that the multi-tasking, single set-up benefits we would gain by using Heckert’s DBF head made even more business sense and has really brought to life Starrag’s philosophy of ‘Engineering precisely what you value’.”
The Heckert DBF machine features an integral U axis that carries Starrag’s innovative DBF multi-tasking head for a wide range of internal and external machining operations. The DBF spindle head comprises a faceplate with integrated work spindle and CNC radial facing slide. For turning on a fixed workpiece, the rotating turning tool – which has an axial runout of just five/six microns – can be radially adjusted by +/- 2.76 in. In addition to external, internal and face turning, the head also permits conical and contour turning courtesy of the radial facing slide’s NC axis. For milling and drilling, the work spindle is arranged in its central position.
Balancing tool wear
Mr Addy confirms that KOSO Kent Introl makes good use of the machine’s 60.35 hp, 3,500 rpm and 1,254 ft / lbf torque spindle by, for example, often applying a high-feed Capto milling cutter on carbon steel (WCB) at speeds of 800 rpm and feeds of 118 ipm. He continues: “The machine is really rigid and on softer materials we are taking cuts of 0.08 – 0.12 in deep – on Duplex bodies, for example, we’re taking 0.12 in cuts at speeds and feeds of 2,362 ipm and 0.01 in / rev. But it is a careful balance between cutting depths and speeds and tool wear; we aim to prolong tool life as much as we can.
This is especially so when milling the rear of flanges – an operation that can be particularly onerous on the wear of the ‘slitting saws’ used. “In addition to working closely with Starrag on the initial fixturing, Starrag engineers also played a key role in helping us establish the DBF process(es) and programming,” says Mr Addy, “which meant the machine was immediately into production and saving us money.”