Operating philosophies of North American sawmills generally treat every log as unique, while European mills tend to pre-sort their logs in the yard for continuous batch processing to achieve a comparable production.

So when Murray Timber Products, Ltd. of Ballygar , Ireland came to USNR for a completely new log line in December 2005, no one predicted that it would result in a new breed of mill operating with a hybrid log processing philosophy.

Murray Timber operates at speeds slower than North American mills, but is able to achieve comparable production. All logs are pre-sorted to within 1 cm, so the mill can run continuous batches of homogenous material with very short gaps between pieces.

New mill replaces mill lost in fire

The mill was replacing a CSMI (USNR) log line that was destroyed by fire. “The CSMI line gave us fantastic service, and since USNR produces even better equipment now, we could see no reason not to go with USNR,” said Production Director, John Murray. “USNR is the Rolls Royce of sawmilling equipment.”

IPL: New hybrid approach blends speed of pattern processing with recovery of optimized sets

“We presort our logs by diameter or pattern into 15-20 sorts depending on length, which are then batched for production runs up to three hours long. In these runs we hold a centerpiece pattern and vary the sideboard products to achieve the best fit per log,” John Murray explained.

USNR’s first pattern-specific optimizer, the IPL (Integrated Processing Line) was developed to allow the mill to combine the high through-put of pattern processing with the increased recovery of sets optimized for each individual log’s 3-D shape.

The IPL allows the basic sawing pattern to stay the same throughout a batch of logs, maintaining a consistent center cant, but allowing variations in the widths of profiled sideboards, and also allowing sideboards to be symmetrically sacrificed (first outer pairs, and then if necessary inner pairs) as needed to achieve acceptable finished material. No edger is needed.

Murray Timber’s European-style linear log line features three cant turners, three profiling modules and four scan zones. The scan data images and resulting optimizer solutions are relayed from station to station successively down the line, enabling just one operator to run the entire line from logs to boards. See diagram below.

Logs are initially scanned by 3D Smart TriCam sensors then move through a quad roll log turner where they are automatically rotated for optimum recovery, and down a single length infeed to a horizontal chipper, creating a two-sided cant.

The two-sided cant is then scanned and turned 90 degrees by a ring turner and lands on a rollcase on the way to the canter infeed. That scanned image is sent to the cant optimizer computer to develop the solution. The two-sided cant is then fed into a second chipper with a skewing infeed that creates a four-sided cant. The four-sided cant is scanned and turned again before proceeding to double profilers.

The profiled cant makes its way to a guided saw Quad Arbor Saw Box to produce sideboards. The profiled sideboards exit to a sideboard dispatch table and transfer to one of the mill's two existing sorters.

The remaining center cant is turned a third time and flows through another profiler, a versa gang also with guided saws, and an outfeed module. The center stack continues on with the option of being split at the splitting saw module that makes the final cut before boards exit to the mill's second sorter.

Mill impressions of the new IPL line

“The shift record to date is 8500 10ft logs. But we expect it to increase because our hourly rates exceed this, and we’ve only been in operation for six months” John declared and added “there is still some fine tuning to be done to ensure consistent through-put.”

Murray Timber is a family owned operation formed by Paddy Murray. His four sons have senior positions in the company’s two mills located in Carlow and Ballygar, Ireland. The company was started in 1978 with a total of four people, but has since grown into an operation with over 140 people.

The USNR line supplied to Murray Timber processes 99% Sitka Spruce with top end diameters from 4-14 inches cut to lengths of 8ft,10ft,12ft,14ft and 16ft. The mill produces a variety of items including pallet, fencing and construction products.

“We’re a one stop shop with 2200 different products,” said Production Director, John Murray. “97% of our production is sold on the domestic market, which is a small country, so we must cater to a wide range of needs.”

“I absolutely recommend this system, and USNR, to other mills,” said John, who has worked at the company for 16 years. “This USNR equipment is extremely strong and resilient. We get good accuracy, through-put and recovery as well as efficient manpower utilization."