Frequently Asked Questions
Q: How much stock can I remove in one pass?
A: Stock removal on a wide belt sander is determined more by the abrasive belt than by the machine. Each abrasive belt is designed to remove a certain amount of stock, and if that amount is surpassed, the life of the belt is affected. As a rule, you will need to use the lower grit belts for heavy stock removal (36-80 grit belts can remove approximately 1/8” to 1/32” respectively) and medium grit belts for lighter stock removal (100- 120 grit belts can remove approximately 1/32” to 1/64” respectively). Belts in grits from 150 on up should only be used for finishing and are not considered cutting belts. Other factors effecting stock removal are: abrasive belt speed, type of sanding head, feed speed, and available horsepower.
Q: Are there advantages to a planer/sander over abrasive planning?
A: Yes. They are mostly related to power consumption and media costs, which are lower with a planer/sander. An abrasive planer will use high horsepower motors with very coarse sanding belts. The latter are expensive, and usually need to be replaced two or three times a week (depending on the type of product being sanded). On average, a planer/sander uses about half the horsepower of a conventional abrasive planer, and the cutter inserts will last several months. These replaceable carbide inserts have four sides/cutting edges; one edge will produce around 150,000 board feet of product. An abrasive planer uses 24 or 36-grit belts, which leave very deep scratches. To remove these scratches, an additional sequence of 60-, 100- and 120-grit sanding belts must be run to achieve the same finish as that produced by a planer/sander running one knife head and one sanding belt.
Q: How many sanding heads do I need?
A: The number of heads required depends on a variety of factors; with some of the most important needs to be considered: the type of wood being sanded, amount of stock to be removed, finish requirement, and feed speed needed to meet production rates.
Q: Should I sand with a drum or a platen?
A: Generally speaking, a drum is used for stock removal and a platen is used for finish sanding; however, drums are also used for finish sanding in some applications. A rule of thumb would be, if you need to remove more than 0.003 to 0.004 inch, you should use a drum, otherwise a platen may be used. The difference between the two is also seen in the finish. A drum will produce a short scratch pattern, but it is deeper on a given grit. A platen will produce a longer scratch that is not as deep. You really need to determine stock removal requirements and desired finish to decide which will fit your needs better.
Q: What is a segmented platen?
A: When sanding veneered panels or sealer/lacquer, utmost control is required. To accomplish this, the platen is made up of individual segments; each of which receive sanding pressure separately (pneumatically or electronically). These segments are controlled by a CNC controller that, along with a sensing unit, can be programmed to activate only when needed. By doing this, you have the ability to conform to the irregularities of the panel to prevent sanding through the sealer or veneer.
Q: What is sealer sanding?
A: Sealer (lacquer) is the first coating applied to your product after finish sanding or staining. The purpose of this is to fill in or "seal" the wood pores and protect the wood. A negative effect to applying sealer is, that being a liquid, it raises the grain of the wood, producing a rough surface. Sealer sanding is performed to create a flat, smooth surface with the proper texture, so that the next coat (also known as the top coat) will adhere properly. Methods used for sealer sanding are: hand sanding, wide belt sanding, brush and orbital sanders (both hand held and feed-through).
Q: When should a cross-belt sander be used?
A: A cross belt sander is used primarily in veneer tape removal applications. The cross belt sander is designed to run across the grain of the wood, which is an aggressive sanding method. Because of this design, veneer tape is removed with one head, whereas two heads are needed with other wide belt methods. Cross belt sanders also are used on long panels in which the grain runs in the narrow direction, such as desk tops and front panels. In processing these, the cross belt is located on the out feed of the machine, so the scratch pattern produced by the belt goes with the grain.
Q: What are hold down shoes, and when do I need them?
A: Hold down shoes in a wide belt sander are similar to chip-breaker shoes in a planer. They are used to control the part as it passes through the machine, prevent dubbed or sniped leading/trailing edges, and to allow for shorter parts to be run. Specific uses are: short or narrow parts, parts under 1/4 inch thick, veneered panels, or any time you need to hold tight tolerances.
Q: When should a vacuum belt be used in feeding a sander?
A: There are two circumstances for which the vacuum belt is appropriate. The first one occurs when you need to run parts that are shorter than the distance from the infeed hold down rolls to the outfeed hold down rolls; these parts may slip or stall in the machine without using vacuum. The second situation is when sanding very thin or flexible parts; parts with a thickness of less than ½” will have a tendency to bow and curl, while flexible product can be lifted into the sanding head. The vacuum belt assists the pressure rolls to flatten and hold the parts during the sanding operation.