'Thin is in' for veneer sanding by Bill Beaty.
Advancements such as segmented platens are making it easier to sand today's thinner veneers.
Veneer production levels for 1991 are predicted to be close to 3.75 billion square feet, up 15 percent from the estimated 3.25 billion square feet produced in 1990, according to Larry Frye, executive director of the Fine Hardwoods/Veneer Assn. With the increased usage of veneer, particularly ultra-thin material, comes the urgent need for accurate sanding of flat veneer panels.
"As the market becomes more accepting of veneers, and as veneers continue getting thinner, you need more sensitive machines. For example, with our wide belt veneer sanders, we have electronic polishing platens which are segmented to follow the contour or shape," said Gary Besonen of SCMI Corp.
Although wide belt sanders are usually the preferred method, drum thickness sanders can also be used. According to Gary Green of Performax Products, the necessary ingredient for flat veneer sanding with drums is tension rollers "and paying close attention to the conveyor and the pressure of the sanding feed."
According to Green, drum sanders used to be the industry standard, but the ease of changing abrasives on wide belts changed that. However, technological advances have made changing the abrasives on drum sanders as easy as on other machines. "I still have some people order a second drum to decrease downtime because of this continued misperception," he added.
The advantage of wide belt sanders continues to be their larger abrasive surfaces which allow the belts to run cooler and load up sanding dust less frequently.
Veneer sanding with wide belts
Through improvements in automated veneer sanding technology, it is possible for small shops to economically sand by machine what was once done by hand, said Besonen, whose company offers many models geared for a wide range of customers.
Segmented platens were the top technological advancement cited by Besonen and other wide belt manufacturers for improved sanding of veneers. Segmented platens vary from standard platens, said Ken Grover of Jenkins Div., Kohler-General, in that each segment works to independently apply the same amount of pressure against the stock. This relieves unequal pressure against the product and lessens the chance for sandthrough.
In addition to segmented pads, Timesavers also installs air, or bladder, pads on its machines. According to Harold Kapaun, the bladder inflates or deflates, depending on core variation, to reduce the chance for sandthrough.
Floating beds were also considered necessary by Jack Grivna of Linden International. The company has offered veneer sanders since 1968. "A floating bed is a must since it helps adjust for warpage." For setup, Grivna suggested referencing off the hold-down shoes versus the conveyor belt, because "whatever is below the shoes is what gets sanded off. With a machine like ours, you should also set up in the floating bed position as opposed to solid bed position to get a much finer feed for adjusting the shoes."
Kapaun, however, said that a negative aspect to hold-down shoes is that the shoe works off the highest part of the veneer. Operators therefore must take care in sanding lower sections of the workpiece.
Gordon Wilkinson of Stiles Machinery suggested setting the machine so that the pad waits until the workpiece is almost halfway under before sanding begins. Although this can create a curvature with regards to the leading and trailing edges, as well as the running edges, it does result in an even sanding of the majority of the panel, he said. Instead of a floating bed, Wilkinson said the DMC Europa machines feature rubber rollers which float the panels.
Six-thousandths is limit
Based on an informal survey, the number one cause for concern in veneer sanding is with the thinness of the material creating sand-through problems. "A lot of the new veneers start out at 12 thousandths of an inch thick. Basically, sanding down to 6 thousandths in thickness is the limit, otherwise you can see glue coming through," said Grivna.
Paying close attention to the core variations and allowing for variations in stock will reduce the chance for sandthrough, Grover added.
"At this point manufacturers are refining machines, making them more forgiving/flexible for veneer sanding. Veneers are not going to get any thicker," Wilkinson added.
"The combination of technology developed to handle the thinner veneers translates into sanding of thinner surfaces, such as lacquers or sealer sanding," Kapaun said. Simple changes, such as belt speed, i.e., 5,000 surface feet per minute for veneer vs. 800 to 900 feet per minute for polyester, enable machinists to use the machines on both materials, he added.
The following are sources for veneer and other types of sanding equipment. For more information, circle the corresponding number on the Reader's Service Card.
Wide belt sanders
SCMI offers two head 37-in., 43-in. and 52-in. machines with the ability to sand both solid woods and veneers. Equipped with Star Delta reduced voltage starters and TEFC motors, each machine has a contact drum and polishing platen with a synchronized anti-dubbing device, variable feed speed and pneumatic sectional pad. The machines are equipped with a power raise and lower table with automatic positioning via an auto set device. 288
The DMC Europa 110 from Stiles Machinery Inc. is an automated machine for light, abrasive planing and thin veneer sanding, with lacquer sanding as an option. It is designed to set up quickly and has an unusually wide 98-in. by 45-in. belt, the company says. Other standard equipment includes: roller bed with eccentric adjustment, floating bed and flexible pad. 289
Sandingmaster Series SCSB-2-1300 Jubilee Machine, from Linden International, features: a simple probe-type setup, power raise and lowering of the table, a variable feed conveyor and disc brakes. The contact roller on the first head operates at 30 hp while the platen on the second head sands at 24 hp. Also available is a veneer package floating table and electric-eye sanding belt tracking. 290
Jenkins, division of Kohler-General, offers a wide variety of Viet automatic wide belt sanders. Included are: Vietmac PL84-2 for veneer and solid lumber, Vietmac PL84 Kombi with capabilities of a two station machine and Hector, for high gloss finishing applications. 291
Available from Stefani Group America, Steemac Star Series are calibrating and lacquer/veneer sanding machines with a heightwise adjustable working table and one or two sanding belts. Specifications include working thickness range of 180mm max and 3mm min, working table height of 950mm and abrasive belt width and length of 1,120mm and 2,150mm respectively. Belt speed of the first unit is 17m/second, and the speed of the second is 14m/second. 292
RAMCO Series 84 wide belt sanders can handle solid, glued-up and framed wood parts, veneered and laminated panels of all types, hardboard and particle-board. Single-, dual- and triple-head models for top or bottom finishing are standard. Sanders are available in 25-in., 31-in., 37-in., 43-in. and 50-in. belt widths. 293
The Butfering-Electronic wide belt sander from Force Machinery has an electronically-controlled segmented pad unit for sanding of veneers and other materials. Features include: tolerance compensation up to 2mm; free, multi-track feeding; and additional equipment which can be used for sanding lacquer or foils. The segmented pad unit also is reportedly ideal for use on workpieces with irregular outlines, workpieces with details or cut outs, concave workpieces, or workpieces with lacquer or filler covering. 294
Model 352-4HD heavy-duty, four-head sander from Timesavers Inc. is equipped with two drums and two platens to enable users to cut down and polish sand in one pass. It includes electronic head adjustment with digital readout and 103-in. abrasive. 295
From Haney Industries, the Pro-Sand Finale conveyor-fed orbital pad cross grain scratch remover features 37-in. or 49-in. width single or double heads with variable feed rates to 15 fpm. According to the company, it can completely remove cross grain scratches in one pass, even on hard rock maple. 296
Jet Equipment says all models of its wide belt sanders, except the 13-in. model, feature power conveyor tables. The sanders have an automatic tracking system on the sanding belt and conveyor belts, amp and load meters, handwheel thickness adjustment and quick reading thickness opening scale. The JWB-37PH features one 37-in. by 75-in. belt, single platen head, 20-hp main motor and variable feed speed of 20 to 79 fpm. 297
Cemco's 2000 Series wide belts feature: working widths from 12 in. to 52 in. with 6 in. working height, belt compensating device, dust-tight electrical enclosures and infeed/outfeed spring-loaded pinch rolls. 298
The Heesemann automatic sanding machine Model LSM 4, from European Woodworking Machinery Co., is engineered as a modular system with up to five cross and longitudinal sanding units in any combination and sequence. Features include: CNC, vacuum bed, electronic control pressure beam and computer-controlled selective pressure regulation system. 299
Boere wide belt sanders, available from Danckaert Woodworking Machinery include the Select series, designed to sand solid wood material. They are available in 43 in. and 51 in. widths with one or two 75-in.-long belts. 300
The Tagliabue TAG T12i from Texwood is a wide belt sander composed of a cross belt with electronic pad, longitudinal belts with a contact roller, and longitudinal electronic finishing pad. 301
The wide belt sander from Halsty Mfg. is available with 10-hp/1-ph, or 15-hp/3-ph motor. The sander has a 37-in. by 75-in. abrasive belt and a combination head with nine-position platen. Electric-eye tracking, automatic emergency stop and load meter are featured on the machines. 302
Powermatic's 25-in., single-phase wide belt sander is reportedly ideal for small- to medium-sized shops that have only single-phase service available. The sander includes a 10-hp, American-made motor with a soft start control to minimize high starting amperage. 303
Bridgewood wide belt sanders from Wilke Machinery are available in single-and double-head models, in 13-in., 25-in. and 37-in. widths, to handle workpieces up to 5 7/8 in. thick. Features include: precise belt tension maintained by constant air pressure, safety interlock switches and dust hoods. 304
Sunhill offers the Sheng Shing SDM-44 and SDM-52 with 44 in. and 52 in. of working width respectively. The SDM-44 has a 25-hp main motor and 2-hp conveyor motor. Feed speed is 12 to 60 fpm. 305
The DA-3760 36-in. wide belt sander from Lobo Power Tools features: two 20-hp main motors, 2-hp feeding and computer-controlled automatic adjusting table. It has a 37-in. max width and 5-in. max thickness. 306
Koch Ltd. Machinery & Systems offers the Medusa wide belt sander in 37 in., 45 in., or 53 in. widths and 103-in. belt length. It features: electronic belt tracking, three-speed heads and shoe-type pressures with roller to ensure constant top pressure without excessive friction. 307
From Progress Machine, Model PMC-132-6 flat bed belt sander features heavy-duty welded construction with leveling bolts. It is powered by a 3-hp, 3-ph motor and has a belt speed of 3,800 sfpm. Features include a dust hood with 4-in. outlet and 6-in.-by-36-in. platen with workrest. 308
According to Performax Products, the 25-in. wide aluminum extruded drums on the new Dual Drum Super Max Sander Model 25x2 are reinforced with an internal framework which circulates the air to keep the drum cool. The design includes built-in sandpaper fasteners for quick, secure attachment. The new abrasive mechanism automatically takes up the slack from the stretching of the abrasives and wrapping the strips directly on the hard surface of the drum prevents oversanding and keeps the edges of stock sharp. 309
The DB-612 sander from Sand-Rite Mfg. is equipped with a 6-in. diameter by 7-in. wide pneumatic drum and #B-12 brush head. The brush head consists of 15 brushes, 4 in. wide, with scored abrasive cloth loaded between brushes. 310
Ekstrom, Carlson & Co.'s 318 pneumatic drum sander offers sanding of irregular shapes and contours. The pliable cushion provided by a slightly inflated pneumatic drum conforms to the contoured shape regardless of grain direction, the company says. 311
Profile, portable and other types
QuickWood, now offers the SAMCO line of profile sanders. The line ranges from a manual abrasive wheel profile sanding machine, Profile V4, up to a feedthrough type sander, Profile V10. The larger machines can be used with abrasive belts as well as profile sanding wheels for intricate contours. 312
The lineal profile sander/polisher with four to six heads from American Machine Corp. is designed for lineal components from 1/2 in. up to 12 in. wide, including mouldings, architectural millwork, cabinets, etc. The sander handles hardwood and softwood, composite board, plastic and ground metal surfaces. Each of the variable speed heads is individually adjustable from the front of the machine; all four sides of the part can be completed in one pass. 313
The Model SA948 compact sander from MAX Mfg. is designed for deburring, graining and finishing operations. It features a 9-in. by 48-in. abrasive belt that operates at 3,850 and 2,100 rpm. The conveyor belt operates at 20 and 10 fpm. Model SA948 has: removable shoes; rubber-covered, spring-loaded hold-down rolls; emergency brake; integral dust hood; precision jack lifts; solenoid tracking; and spring-loaded belt tensioning. It can handle parts 5 in. by 9 in. by 0.01 in. to 3 in. thick. 314
Lightweight air sanders for use on wood, metal, stone or plastic are available from Nitto Kohki. The LS-10 line sander has no gears, uses very little air and is built for continuous use. Model OSB-60/50 orbital sander/polisher produces a swirl-free finish, the company says, and does not cause operator fatigue. FS-100C free sander is driven by a turbine motor mounted directly on the sanding pad, thereby minimizing vibration. 315
Whirlwind Model 700 mould sander is for use on raised panel doors. Made of heavy-steel construction, it features a tilting motor and infinitely variable speed. A Baldor constant torque motor with an SCR controller allows users to dial in any speed from 0 to 1,800 rpm. 316
Black & Decker's 4011 palm grip sander features a dual-grip body design enabling multiple positions for one-handed sanding. A zipperless dust bag ensures quick disposal; an optional adapter for dust extraction hoses is available. 317
The Mini-Dynorbital air-powered random orbital sander from Dynabrade has 3/4-in. and 1 1/4-in. diameter pads and speed adjustment for 0 to 5,000 rpm. It can be used on wood, metal and composite boards. 318
TurboBrush woodworking brush machines from Kuster Mfg. are reportedly ideal for: white wood sanding, cleaning, denibbing, sealer sanding, stain wiping and scuff sanding. The company says applications are unlimited since the machine can conform to non-uniform surfaces. 319
From Fein Power Tools, the MSX 636 sander oscillates 20,000 times per minute, allowing for quick and effortless corner and edge sanding of wood, plastic and metal surfaces, the company says. It can be used on window frames as well, even against glass. 320
Balestrini's double-sided CNC mould sanding machine from Solid Wood Systems comes with four to eight processing units moved by DC servomotors. Ball recycle screws are used with relevant nuts prestressed to zero backlash. 321
The Bacci FX automatic profile copying, milling and sanding machine from Richard T. Byrnes Co. Inc. can profile two sides of a workpiece in one pass, sanding and copying. The basic unit has four, six or eight heads for knife cutting applications or, when purchased with oscillating units, for sanding and smoothing. 322
Mereen-Johnson Machine Co.'s Model 600 Series contouring machine for the kitchen cabinet industry shapes, profiles and sands cathedral-type panels and rails. An infeed measuring system automatically retrieves the proper computer program memory, which allows for feeding of random width boards and running of smaller lot sizes, the company says. 323
The Technolegno automatic one-sided moulding and sanding machine distributed by Derda Inc. shapes and sands profiles in a single pass. The company says high accuracy is achieved by using retractable dogs in the feed chain to hold the workpiece securely as it passes through the shaper unit and along the feed table to profile sanding units. 324
Delta International Machinery Corp.'s 4-by-132-in. edge sander offers edge and profile sanding capabilities. The straight side table bias tilts 10 [degrees] and moves up or down across the platen. The form side table tilts 45 [degrees]. Features include: graphite platen pad, spring-loaded idler pulley tension with single-knob belt tracking and flip-up guard end caps. 325
Atlantic Machinery Corp. offers the Griggio GL 3000 stroke sander for a wide range of sanding operations on various sizes of work. Features include: automatic raising table more than 9 ft long, 5-hp main motor with overload protection and magnetic starter, and 6-in.-by-26-ft belt. 326
The A111 profile shaper/sander from Voorwood Co. is designed to shape and sand the edges of cabinet doors, furniture parts and manufactured wood components, producing a smooth finished surface on wood, MDF and particleboard, the company says. More than 8,500 lineal feet of finished product is possible on the A111 when running at a feed speed of 18 fpm in an eight-hour shift. The company says a broader range of profiles can be sanded when adding the Turbosand rotary head system. 327
The Oscie 60 edge belt sander from Crouch Machinery features a 60-in. platen, 5-hp drive motor and 6-by-159-in. belt. A device allows the operator to move the table in eight directions: up, down, in, out, bias tilt and 30 [degrees] forward, 45 [degrees] back. 328
The R-700 Series of horizontal edge belt sanders from Ritter Manufacturing Inc. features: 4-by-132-in. belt size, double 4-by-49-in. steel platens, 1 1/2-hp single-phase motor, manual controls accessible from both sides, dust hoods with 4-in. end openings, pedestal base and two 12-by-65-in. bias tilting tables. 329
Fortis Machinery Corp. offers the new ES489 oscillating edge belt sander. It has a 6-by-124-in. sanding belt, 47-in. platen, platen tilt from 0 to 45 [degrees] and 3-hp motor. 330
The Fletcher FM-30 non-oscillating edge sander for large and small manufacturers has: a 5-hp, 1,800-rpm motor that is totally enclosed, manual starter with overload protection, graphite-covered 8-by-48-in. metal platen with adjustable takeup and dust hood. 331
Delle Vedove USA Inc. profile sanding machines sand unfinished or lacquered pieces in a variety of complex shapes, automatically at high speeds. Machines are custom built and can be equipped with belt sanders, abrasive wheels and special units for handling intricate forms. 332
Tekmatex Inc. offers the Shimura 600 CNC profile sander which can be changed from one sanding profile to another within 30 seconds, the company says. A liquid crystal display shows exact positioning of all heads. Correct pad pressure and sanding belt tension are automatic. The machine will sand edge and mould profiles. 333
Diehl Machines' Model PS10 spindle sander does irregular shape sanding, horizontal belt sanding and vertical belt sanding. The company says it can save up to 80 percent in sanding cloth and one to two separate operations in sanding irregularly shaped moulding. Options include an overhead belt conversion unit. 334
The Ghermandi SRL Caliber 300 bottom belt calibrating and sanding machine is offered by Foley United Co. It is manufactured with either mechanical or pneumatic control of oscillation and sanding belt tension. 335
Woodworking Machinery Imports' Adler 3000 stroke sander is heavy steel with a 120-by-32-in. sliding work table with wood slats for stock support. Vertical adjustment is 30 in.; horizontal travel is 28 in. Belt size is 6 by 306 in. 336
PHOTO : Sandingmaster Series SCSB-2-1300 Jubilee from Linden features a simple probe-type setup.
PHOTO : From European Woodworking, the Heesemann LSM 4 has an electronic control pressure beam.
PHOTO : The table on SCMI's CL Series has automatic positioning via an auto set device.
PHOTO : Abrasive slack is eliminated on Performax's Dual Drum Super Max Model 25x2.
PHOTO : Delle Vedove profile sanders sand unfinished or lacquered pieces in a variety of complex shapes.
PHOTO : The DMC Europa 110 from Stiles Machinery performs light, abrasive planing and thin veneer sanding, with lacquer sanding as an option.
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|Title Annotation:||includes related article by Bill Beaty; advances in veneer sanding|
|Author:||Koenig, Karen Malamud|
|Publication:||Wood & Wood Products|
|Date:||Jan 1, 1991|
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