Sus­tain­abil­ity-driven saw line

Tropik Wood in­creases re­cov­ery to sup­port build­ing boom

Australasian Timber - - MANUFACTURING TECHNOLOGY -

Ap­prox­i­mately 2500 Fi­jians, in­clud­ing the coun­try’s Prime Min­is­ter, cel­e­brated the startup of a new Söder­hamn Eriks­son/

USNR saw­line at the Tropik Wood’s Drasa mill in Lau­toka, Fiji. The new equip­ment re­places an old saw­line and al­most dou­bles the mill’s tim­ber re­cov­ery.

Founded in 1987, Tropik Wood In­dus­tries Lim­ited (Tropik) is the largest pro­ducer of tim­ber prod­ucts in the coun­try. Pro­cess­ing Caribbean pine, the 170-em­ployee com­pany pro­duces more than 15 prod­uct types, both treated and un­treated, rang­ing from pro­filed tim­ber, con­struc­tion ma­te­rial, and posts and poles for do­mes­tic cus­tomers, to wood chips for ex­port mar­kets. Waste ma­te­rial feeds a biomass power gen­er­at­ing plant.

Project goals

The mill was us­ing equip­ment pur­chased in 1987 that fo­cused on vol­ume rather than re­cov­ery.

This did not match the com­pany’s and the gov­ern­ment’s goals for op­ti­miz­ing the use of the is­land’s nat­u­ral re­sources.

Four years ago, Tropik de­cided that ma­jor cap­i­tal up­grades to their sawmill line were needed. “The old mill ex­pe­ri­enced long down­times and very poor re­cov­ery,” said Vim­lesh Ku­mar, Tropik Wood’s Project Man­ager. “The low av­er­age re­cov­ery of 27% meant that we were wast­ing our valu­able saw logs, which take 25 years or more to ma­ture for tim­ber.”

Tropik con­sid­ered sev­eral al­ter­na­tives in­clud­ing buy­ing re­fur­bished ma­chin­ery from Canada or New Zealand, but opted for new, top-of-the-line equip­ment for greater cer­tainty of pro­duc­tiv­ity in­creases over the next 15 years.

The process: De­bark­ing

Caribbean pine logs en­ter the sawmill un­sorted lead­ing with the small end. Logs range from 15 - 50 cm di­am­e­ter in lengths of 3 - 6.1 me­tres. Logs are scanned and op­ti­mized, with 2.8 - 3 m gaps at the in­feed. Pro­cess­ing logs with small ends first pro­vides ad­van­tages in more ac­cu­rate in­feed align­ment and for edg­ing ac­cu­racy.

Logs en­ter the de­bark­ing line at con­sis­tent in­ter­vals. The Cam­bio 800 is a heavy duty high-speed de­barker that ac­com­mo­dates all log sizes, and is par­tic­u­larly suited for logs up to 795 mm in di­am­e­ter. It of­fers re­li­a­bil­ity, min­i­mal ser­vice re­quire­ments, and ul­tra-low op­er­at­ing costs. Tri­an­gu­lar feed works and car­bide tipped de­bark­ing tools ac­tu­ated by com­pressed air are im­por­tant fea­tures to achieve first class de­bark­ing re­sults.

Tropik Wood paired the Cam­bio

800 with the CIM De­barker In­feed. This in­feed’s auto-cen­tring func­tion feeds logs with no gaps, max­i­miz­ing de­bark­ing line pro­duc­tiv­ity. The CamTrail de­barker out­feed pre­vents logs from wob­bling or ro­tat­ing dur­ing the process. Once de­barked, logs pass through a me­tal de­tec­tor, to a log kicker, el­e­va­tor, and sin­gu­la­tor, then on to the saw­line scan con­veyor.

The process: Chip­ping, cant­ing

Once scanned, a 3D data model is pro­duced and the op­ti­mized saw pat­tern pro­vides log and cant break­down so­lu­tions. Log ro­ta­tion is achieved with the 750E ro­tary log turner con­trolled from the PLC and ac­tu­ated with an elec­tric servo mo­tor.

Next, the LogPos in­feed po­si­tions the log with 4 pairs of ver­ti­cal side rollers on a chain bed. The side rollers have spikes to hold the log’s ro­tated po­si­tion securely while feed­ing into the cut­ting tools. The in­feed of­fers side shift ca­pa­bil­ity of ±30 mm and fol­lows the path de­fined by the saw­line op­ti­mizer to achieve ac­cu­rate open­ing faces on both sides. Spiked rolls firmly se­cure and feed the logs into the chip­per can­ter unit.

The Chip­per Can­ter with Com­biSpi­ral discs was cho­sen be­cause it pro­duces first class pulp chips, and boards with smooth sawn faces and proven di­men­sional ac­cu­racy. With a wide va­ri­ety of ac­ces­sories, it can be cus­tom­ized for log or cant break­down, straight or sweep saw­ing and for pro­duc­tion speeds up to 150 m/min.

The process: Saw­ing

The quad band­saw max­i­mizes pro­duc­tion and per­for­mance with thin kerf saws. It is de­signed for high prod­uct ac­cu­racy at feed speeds up to 120 m/min. Two to four side­boards are sep­a­rated at the board sep­a­ra­tor, and dropped onto the edger con­veyor.

The cant is turned 90 de­grees and con­veyed to the Cant Feeder 435 which po­si­tions it in front of the sec­ond chip­per can­ter; it is cen­tered, side shifted and skewed for the most ac­cu­rate curve saw­ing fol­low­ing the cant’s nat­u­ral shape.

The curve sawn cant en­ters the sin­gle ar­bor cir­cu­lar saw with 4 shift­ing saws and the op­tion to mount ad­di­tional saws on the outer shafts. Side and cen­ter boards are sent to the green chain. Side boards are man­u­ally sep­a­rated and sent to the op­ti­mized edger.

The process: Edg­ing

The Cat­ech 400 edger line in­cludes an S-shaped un­scram­bler, trans­verse scan­ner with con­veyor, edger in­feed and 3-saw edger, edg­ings sep­a­ra­tor, and board out­feed. The edger line of­fers high speeds and top re­cov­ery with op­ti­mized wane con­trol, and a split saw for pro­cess­ing wide boards.

The in­stall

One of the chal­lenges we faced was in­te­grat­ing new equip­ment into an old fa­cil­ity with in-place in­feed and green chain. “The costs of mov­ing ev­ery­thing would make the project com­mer­cially un­vi­able,” said Faiz Khan, Fiji Pine’s Ex­ec­u­tive Chair­man. “To in­crease our chance of suc­cess, we en­gaged the ser­vices of Skookum Tech­nol­ogy, the process en­gi­neers (and Söder­hamn Eriks­son/USNR’s agent) out of New Zealand, to re­view our plans and en­sure a smooth ma­chine in­stal­la­tion.”

“Another chal­lenge was the iso­la­tion fac­tor,” said Vim­lesh. “It takes al­most two months for ship­ments to reach Fiji from Swe­den.” As if these chal­lenges weren’t enough, a ma­jor cy­clone hit the is­land in the mid­dle of the project. “De­spite these fac­tors, and the time zone dif­fer­ence be­tween Fiji and Swe­den, the project was im­ple­mented on time,” said Vim­lesh.

Re­sults

The new mill has a ca­pac­ity of 350m3/day, how­ever, it is cur­rently be­ing run at a daily av­er­age of 180m3 to en­sure sus­tain­abil­ity of the is­land’s forests. As a re­sult of the new equip­ment, tim­ber re­cov­ery has in­creased sig­nif­i­cantly. The new line also of­fers greater flex­i­bil­ity and can han­dle larger di­am­e­ter logs.

For Söder­hamn Eriks­son/USNR, this was a unique and chal­leng­ing project. Lars Lind­vall com­ments: “We knew this project was go­ing to have sig­nif­i­cant chal­lenges, but we were pleased to be able to out­fit this op­er­a­tion with state-of-the-art equip­ment that will serve Tropik’s in­ter­ests for many years to come.”

A flitch is fed into the Cat­ech edger ma­chine.

Logs are ro­tated with the 750E log turner as they en­ter the LogPos po­si­tion­ing in­feed for se­cure feed­ing into the cut­ting tools.

Cam­bio 800 de­barker with CIM 750 In­feed.

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