New developments in sanding technology.

Multiple-task capability, decreased set-up time and more ease in producing a quality end product are results that industry experts are attributing to recent technological updates in feedthrough sanding machines.

Wood & Wood Products surveyed sanding machinery distributors and manufacturers with regard to new developments in sanding equipment technology. The consensus: a quality finish in the end product hinges upon a proper equation involving the material being sanded, the machinery and methods used in the sanding plus the time and effort involved in the process.

One question asked was: "What are some new developments in sanding equipment technology and how are they helping users become more productive?"

Following are some edited responses to this question from sanding equipment suppliers.

Harold Kapaun, national sales manager, Timesavers: "Three of the newest sanding technologies are combination knife planer/sander, feedthrough orbital sander and sealer sander.

"The combination knife planer/sander uses a cutterhead followed by one, two or more abrasive belts. The cutterhead in the first stand: has reduced horsepower requirements and abrasive costs, and higher feed-speed rates and more accurate tolerances have been achieved. In the past, glued-up panels were planed using 36-grit abrasives. This would require an abrasive sequence of 60/100/120 to remove the scratch pattern. The smooth surface of today's cutterheads requires approximately 0.010-0.012-inch stock removal, thus 120-grit abrasive is used.

"Recent additions to feedthrough orbital sanders have been combination machines using widebelt sanding heads, followed by orbital heads, followed by denibbing brush units. Orbital sanders are used primarily to remove the scratch pattern produced by widebelt sanding and/or stroke sanding. A second use for this particular machine is sealer/lacquer sanding.

"The woodworking industry, in conjunction with many major machinery manufacturers, is constantly developing new and improved ways of sealer sanding. Sealer sanding can be performed by use of widebelt sanders, brush machines, hand sanding, rotary brush machines and feedthrough orbital sanders. It has been seen, and further developed, that the denibbing of material by any of the above methods in the white wood state has greatly improved the product prior to stain and seal. Having a properly prepared surface has decreased the amount of labor used in subsequent processes."

Dean Sager, sales manager, Tekna Machinery: "Computers increase productivity by decreasing operator set-up time and operator error. By saving computer programs of all the different individual materials to be sent through a sanding machine, operator set-up time and error is greatly reduced. There is no more manual set-up of several different items on the machine to run each individual piece of material. It is all handled by calling up a single program for a particular piece of material which pre-sets everything on the machine.

"Electronic sectional pads have greatly reduced sandthroughs of veneers and lacquers, which in turn has greatly increased operator productivity through less operator error, material rework and material handling."

Scott Grissom, Costa & Grissom Machinery Co. Inc.: "This question is always the same. And it seems the answers from most sanding suppliers are always the same: computer controls, electronic segmented pad units, etc. Yet, instead of trying to use the widebelt sander as a cure all, why not eliminate the problems before they get to the widebelt sanding operation?

"Manufacturers are starting to realize that if the panels are fairly flat and if the overall panel tolerances are tighter, they not only see significant improvements in sanding quality, but in other machining operations as well. The answer to this is core calibrating.

"If a manufacturer would realize the importance of care calibrating, then the extra expense of copying heads on a combination machine would not be needed. If the panel is flat, there is no need to copy it. In short, the tolerances of all machines throughout the manufacturing facility would greatly improve.

"The last thing to consider is final product. If the panel is processed right from the beginning of the operation, the finish will be more uniform, thus helping to produce the best finish possible."

Stephan W. Waltman, vice president of sales and marketing and interim product manager - veneer group, Stiles Machinery: "As in most areas of the woodworking industry, the use of electronic control technology is helping the woodworker become more productive, from a simple terminal to control belt speed and feed speed to integrated technology that can memorize the set-up of the entire machine by part number or bar code. By adapting such electronic aids, the sanding technician can greatly reduce his set-up time and increase quality."

Mike Hamer, Sunhill Machinery: "We are seeing a lot of interest in 15-inch wide-belt sanders that feature open throat design with smaller footprints and smaller power requirements. Advances in technology mean [+ or -]0.001-inch accuracy side to side. Adjustments to the hardness of the contact roller mean extreme accuracy in sanding, even for sanding laminates of very close tolerances.

"We think staying with pneumatic tracking provides reliable performance with a tried and true technology, as opposed to the high service and replacement parts cost associated with electric-eye tracking systems. Keeping the 15-inch sander simple, with no platen and a single head, keeps costs down and makes high-quality sanding equipment available to small shops at reasonable prices.

"Improvement to dust collection design, closer to the head with open throat full-length of the contact roller, means more efficient waste removal, less dust in the shop, and a healthier workplace."

Chris Derda, Derda Inc.: "Past technology for abrasive belt units for profile sanders has included a rigid design of the sanding pad mechanism on the units. The rigidity of sanding pad entry produces a calibrating effect on the edge. In other words, the pad stays in the same rigid position and does not follow the natural contour of the moulded profile. The belt cuts through variations in the material.

"Today's pad mechanisms are more forgiving and more versatile. They can be adjusted to follow the contour of the edge. This produces a smoothing rather than a calibrating effect on the edge.

"Set-up time on abrasive belt sanding units is usually a process of trial and error until the correct positioning of the abrasive pad is obtained. The new forgiving design usually allows the operator to obtain a good sanding job on the first few trial pieces.

"Cathedrals and other shaped edges can now be sanded using an abrasive belt unit. When possible and economical, abrasive belts should be used to sand curved surfaces without intricate detail. In the past, most sanding of shaped edges has been done using abrasive disk units. But now, thanks to a computer-assisted design, the belt units follow the contour of the panel. The use of Allen-Bradley computers allows for easy parts replacement. The programs are equipped with a self-learning feature to assist the operator in learning to use the machine.

"Ultimately, reducing or eliminating difficult-to-use technology or hand sanding will reduce time constraints and labor costs and will lead to higher productivity and production capability."

Doug Armitage, technical sales manager, Force Machinery: "Recent technological developments in wide- and crossbelt sander designs have had a dramatic effect on the way woodworkers look at surface improvement and quality in finish polishing. The cost of this technology has come down into the range of the smaller manufacturer, and the machines are simple to operate and consistent in uncalibrated materials.

"In many applications, where traditional sanding machines have been upgraded, hand work and orbital sanding have been eliminated completely and new methods of finishing can be implemented with a measurable result on the bottom line, and a definable improvement in quality and consistency.

"The woodworkers I have spoken with have all reported that in order to take advantage of the newer machine's advantages, they have changed the way they look at the actual function of sanding in their production. This has not always been easy. Traditional sander design is concerned with stock removal. The modern finish sander is primarily concerned with providing a defined surface quality for application of modern finishing materials. This is very different in concept from the massive, heavy horsepower standard designs of yesterday."

Available Equipment

The following is a review of some sanding equipment available to the woodworking industry. For more information, circle the corresponding numbers on the Reader's Service Card or consult the 1996 Red Book Annual Buyer's Specification Guide.

Widebelt sanders

The Series 500 knife planer/sander from Abrasive Engineering & Mfg. features a spiral cutterhead in the first station. The unit can be used for jobs requiring dimensioning and sanding of edge-glued lumber, banded particleboard and core stack materials.

Cemco, in an agreement with Don Haney, manufactures an updated version of Haney's cross-grain orbital sander. The units are available in three widths (37, 43 and 52 in.) and can be equipped with both widebelt abrasive heads and angled brush denibbing heads. The ratio of usable abrasive media is over 60%.

The Jubilee series Vega sanding machines, available from Force Machinery, features a programmable terminal to control feed speeds, CPS segmented pad, variable edge pressure, pre-selection of workplace thickness, hour counter and timer.

The Halsty widebelt sander has a 37-in. x 75-in. abrasive belt, 8 1/2-in. working height, combination head with nine-position platen and four-speed conveyor belt.

The JMB-37B 36-in. widebelt sander from Jet Equipment & Tools features a 20-hp motor and variable feed speeds from 16 fpm to 62 fpm. It can handle workpieces as thick as 5 in., the company says.

The 37-in.-wide abrasive belt machine from S.J.G. Machinery Inc. features a 5-in.-diameter contact roller followed by a 3-in.-wide polishing platen. Additional features include a 75-in.-long abrasive belt, table power raise and lower, a 15-hp main motor, and controlled variable feed speeds.

The Model Pro-3000 37-in. widebelt sander from Woodmaster Tools Inc. features single- and three-phase motors with infrared tracking, motor load meter, metal disc brake and variable feed speed.

The Lobo A-3760 widebelt sander has a 20-hp motor powering a 37-in. by 60-in. abrasive belt which is accessible by a full opening side door. The feed table has a 2-hp motor with spring-loaded infeed-outfeed hold-down rollers, and six different computer-controlled speeds and an LED indicator for thickness control.

The Heesemann MFA8 automatic, multi-purpose surface sander available from Stiles Machinery Inc. uses CSD-pressure beam technology that controls sanding pressure. The MFA8 is capable of veneer, lacquer and foil sanding; calibration and finish of sanding of solid wood; processing cross and longitudinally veneered parts; alternating small and large series production; sanding warped and differently tolerated parts and sanding a variety of shapes from round to rectangular.

Tekna Machinery's newest addition to its DMC widebelt sander line is the FINESAND orbital sander, designed to remove cross-grain scratches left by longitudinal widebelt sanders. Table feed speeds for the one head orbital reaches 30 rpm. Other features include a vacuum bed, 52-in. table width, Tynex brushes and two orbital heads on one matching base.

The Sandya 10 RRCS 43-in. sander from SCMI comes with a 7-in.-diameter steel calibrating drum, a 7-in. 65 durometer pre-sanding drum, and 7-in. 45 durometer finishing drum with a 2 1/2-in. polishing platen. Other features include a variable feed speed mat, the capability of raising and lowering the feed table from the control panel, floating pressure shoes and a foot pedal to control table positioning. SCMI also offers a veneer package with electronic sectional pad for a high-quality finish and no sandthrough.

Costa & Grissom Machinery offers the Costa Model 60 widebelt sander designed as a production machine available in two or three working units. The Model 60 comes equipped with 103-in. sanding belt lengths, pneumatic grit-sets, electronic segmented pad units, variable feed speeds and variable cutting speeds for sanding solid wood, veneers and sealers and lacquers.

The SDM-15 15-in. widebelt sander available from Sunhill Machinery, has an open-end design which enables it to sand up to 30 in. wide. The machine's second edition features two speed feed rate and the main motor has been moved inside the base to reduce the machine's foot print.

The model 252-71CTB combination bottom head and top head sander from Timesavers is designed for processing furniture components, cabinet doors and face frames, solid wood and panels. The 252-71CTB features TEFC motors, digital thickness readout, conveyor belt tracking, over-thick shut-off protection, Posi-trak electronic abrasive belt tracking, dial indicators on adjustable contact drums and platens, cam adjustable spring-loaded holddown shoes, and percentage load meters.

The Boere widebelt sanders and polishers Series T and B from Danckaert Woodworking Machinery Co. incorporate a "floating bed" pneumatic lamellas system and holddown shoes for the sanding of veneers. The system provides instant reset of the bed's configuration and shoes for thickness calibrating operations. The available features include top or bottom machines with one to four sanding units each, vacuum feedtables, variable feed and belt speeds and electronically controlled segmented, air-loaded polishing platens.

Wilke Machinery Co. says the new Bridgewood BWS-15 features an open-end design that allows the 15-in. belt to sand up to 30 in. wide and 6 in. thick by passing the work through twice. The machine also features an 8-in. diameter, cushioned sanding drum, a choice of main U.S.-made motors (5-hp, 1-ph or 7.5-hp, 3-ph), pneumatic belt tensioning and tracking and a tread rate of 15.4 fpm.

The Model RB37 37-in. widebelt sander from Powermatic, with a 37-in. by 60-in. sanding belt, is equipped with a 15-hp, 3-ph 230-volt motor and magnetic controls. The two-speed feed system (15 fpm; 30 fpm) is driven by a separate 1-hp motor. Powermatic says the "air-jet" sensor and diaphragm valving system controls the belt oscillation and virtually eliminates conventional tracking problems.

Profile & Edge Sanders

The Stemas LEV P.A. Baby 2000 one-sided edge and profile sanding machine available from Derda is equipped with one belt sanding unit and one sanding/polishing disk. The machine can sand straight, contoured (cathedral-type) profiled door and panel edges and mouldings.

Delle Vedove offers profile and edge sanding machines that can sand a wide variety of pieces and can be equipped with various belts, abrasive wheels and special units for handling intricate shapes.

The 300/Gyro profile sander from Fladder Systems allows for uniform stain penetration, smoother sealer of primer coat and minimum grain raising. It is available in 52 in. and 39 in. widths.

The LTC 4 profile contour sander from Makor USA Inc, features 40-200 fpm feed speeds, and can sand veneer, plywood, particleboard and other materials. It features four sanding heads.

The ES Series of edge sanding machines from Tagliabue America are available in-single- or double-sided versions. Maximum workpiece thickness capabilities are 100 mm for all machines, and feed motors can range from 2 to 4 hp.

The P.A.O. Macc automatic profile sander from Tech Mark Inc. is equipped with a material transport system which controls the alignment of the moulding, special 100mm-wide drive belts to ensure uniform speeds, a solid bed plate under material for positive pressure for the sanding head and easy-to-adjust guides.

Tecnolegno offers a selection of single-and double-sided profile sanders. The sanders are equipped with PLC units to control each working head.

The Model 320 Shape and Sand System from Unique Machine & Tool Co. shapes parts and then sands the parts with its feedthrough system. Variable speed controls and multiple stations allow for finish sanding to be completed to exact requirements. In addition, the machine is capable of sanding arches and shapes.

The Voorwood A178 Shaper/Sander provides feed through profile edge shaping and sanding in a single pass through the use of precision shapers and Voorwood's patented Turbosand system. The A178 operates at variable speeds up to 35 fpm and has tooling available in nearly 1,000 stock patterns. Custom profiles can be created.

The LASM Series profile sanders from Atlantic Machinery Co., including the 1NR model, are available with an optional revolver system able to store up to six different pads for as many profiles. This system cuts down set-up time between runs with only a few seconds needed to rotate the right pad into position. The sanders are now also available with optional digital readouts.

Designed and built in the U.S., Ritter edgebelt sanders are offered in widths of 4 in. or 6 in., with a double-sided ground steel platen lengths up to 60 in. standard. Both fixed or oscillating platen models are available with drive motors up to 5 hp with overload protection. All models feature end tables with contact drum and spindle sanding units, and bias tilting tables allow for a variety of angle sanding applications with full belt width utilization.

The Heesemann LSM 8, available from IMA-European Woodworking, features the patented CSD system, an electronic pressure beam system for sanding odd-shaped workpieces, longitudinal and cross grains and thickness variations of up to 3/32 in. without set-up changes.

Performax Products Inc. says its four SuperMax models, now with the company's SandSmart control, offer 25-in. or 37-in. single or dual drum sanding capacity. Standard features include tension rollers, depth gauge, hinged steel cover with 4-in. vacuum port(s) and a 5-hp motor. They are equipped with self-cooling drum(s) with patented take-up fasteners and a heavy duty no-give power feed conveyor.

Kundig Sanding Machines says its Primo widebelt moulding sander with CNC control can create profiles with depths up to 0.4-inch through the use of its Windows-based software and extensive database. Profile definition can be downloaded as a file and directly merged with a program. Other features include precise ball guides, dynamic servo drives for feed and height adjustment and separate CNC control console built by Industrial Computer.

The Walter Hempel automatic sander Type PC-5, available from Henry Wiegand Corp., is designed for sanding oval or flat pieces such as hammer handles, flat paint brush handles, etc. The workpieces are placed into a hopper, automatically taken up, clamped and led along a series of sanding belts fitted on an oscillating rack.

RELATED ARTICLE: WIDEBELT SPEED BASED ON MATERIAL FEEDS...

Matching machine feed speeds and grit sizes to obtain the best possible finish on a widebelt sander hinges on the type of material being sanded, coupled with the material's end use.

"Best finish is very subjective from customer to customer," said Mike Hamer, of Sunhill Machinery. "The big advantage of widebelts is that the large surface area of the belt, combined with belt oscillation, means overheating and burning of work when using fine grits (180-220) is not a problem, even in materials with knots or variations in thickness. In most cases experience on the machine and knowledge of materials is the customer's only sure guide to a best finish."

With this in mind, achieving optimal machine performance in regard to the best possible finish in the end product requires a knowledge of the material being sanded, the machine being used, the grit of the sanding belt and the end use of the finished product.

"The bottom line is that there is no 'rule of thumb,'" said Scott Grissom, of Costa Grissom Machinery Co. "Yet the most important thing was left out of the equation: cutting speeds. In reality, not theory, everything that is sanded actually requires a different cutting speed. It also goes back to what kind of sandpaper the end user is using." He continued, "The best and only guideline to follow is this: Achieving the best possible finish in the widebelt sanding department depends solely on one thing, a marriage between the end user, the widebelt sander supplier, the sandpaper supplier and the finishing material supplier. Only when these four groups work together will the best finish possible be achieved."

Dean Sager, sales manager at Tekna Machinery, agreed in that it "all depends on what you are sanding."

"When sanding solid woods with a 36 grit and calibrating a lot of wood," Sager said, "you will move at the slowest feed speeds. When lacquer sanding, you use very high grits of 240 or more and the table feed speeds will be very high so that the abrasive grit does not heat up."

Harold K. Kapaun, national sales manager for Timesavers, explained, "Most widebelt sanders are equipped with a percentage motor load meter monitoring the amperage being used by the main motors. An experienced operator can tell by watching the percentage load meter whether the correct amount of stock is being removed by each abrasive head. The percentage load meter is also used as a tool so as not to overload a given abrasive grit, thus causing immediate loading and/or damage to the abrasive belt.

"It is recommended," Kapaun added, "that to achieve the highest abrasive belt life and reduce electrical costs, whenever possible butt (back to back) feed product. By running material back to back, the abrasive belt does not see the normal leading and trailing "shock" loads caused by a workpiece. There is a smooth transition from the first part to the second part. By reducing the shock load to the abrasive belt and also reducing the electrical surges which would occur if this process is not used, the highest possible abrasive belt life is achieved with the lowest electrical consumption."

Kapaun also added, "It is recommended that not more than one abrasive grit be skipped when going from the first head of a widebelt sander to the second head. Not skipping more than one abrasive grit allows the following abrasive to remove the scratch pattern of the previous abrasive. In recent times, the high-end customers are not skipping any abrasive grits. An example would be on a typical four head widebelt sander where the abrasive grit sequence would be 10/120/150/180 or 120/150/180/220 to achieve the finest possible sanded surface."

According to Doug Armitage, technical sales manager, Force Machinery Co., "Feed speed in a widebelt at a given abrasive speed will have less to do with finish quality than the type of material and abrasive type. We train operators to run at the highest speed that any given production situation can afford them. Belt life suffers at lower feed speeds, and improper abrasive belt loading in high stock removal situations will cause surface defects."

Stephan W. Waltman, vice president of sales & marketing. Stiles Machinery, said, "It's difficult to give any (specific) guidelines. There is a direct relationship of belt speed to finish quality, but this must be evaluated differently if a cross belt is used. Regardless of the grit size of the cross belt, the operator must adjust the belt speed to match the overlap required for adequate stock removal. And this is always subject to the process parameters and outcome expectations."

- J.R.