Información técnica sobre bruñido

Después de casi 100 años en el negocio del bruñido, Sunnen tiene una gran cantidad de información técnica útil que compartimos con gusto con nuestros clientes y con la industria en general. Los expertos de nuestro departamento de Servicios técnicos han recopilado los siguientes consejos, términos y guías de bruñido para ayudarlo a optimizar sus operaciones de bruñido.

Si aún tiene preguntas después de revisar los documentos correspondientes para su aplicación de bruñido en particular, no dude en contactarse con Sunnen para obtener asistencia técnica adicional.

¿Qué es el bruñido?

El bruñido es una operación de acabado que se lleva a cabo sobre una superficie, por lo general de un cilindro interno, como el de un bloque de motor automotriz. Este proceso de eliminación de metales se utiliza después de las operaciones de fundición, sinterización, taladrado, mandrinado y otras para lograr una geometría y un acabado superficial precisos del orificio. Abrasive stones are used to remove minute amounts of material in order to tighten the tolerance on cylindricity.

Durante la última década, el bruñido se ha convertido en un proceso que se describe mejor como  acabado de orificios porque tanto la cantidad de virutas que se eliminan como la velocidad a la cual pueden eliminarse han aumentado de manera considerable.

To learn more about honing, download our booklet Honing Technology, Tools and Machines.

Breve historia del bruñido

El concepto del bruñido, un movimiento predeterminado de rectificación y la eliminación de virutas de toda clase de materiales, nació hace siglos. En el siglo XVI, Leonardo da Vinci inventó una herramienta para el mecanizado de tubos de madera. La herramienta consistía en una combinación de movimientos de rotación y carrera, e incorporaba un granulado abrasivo.

Las herramientas de bruñido, tal como las conocemos ahora, se inventaron al comienzo del siglo XX, principalmente para mejorar los componentes del motor de combustión interna. Las primeras herramientas de bruñido eran varas de madera con papel de lija. Las varas golpeaban contra las paredes de los cilindros por acción de resortes. Pronto, se desarrollaron herramientas más complejas. En 1924, se patentó una herramienta de bruñido que consistía en una vara con cinco paletas, con una junta universal y alimentación por resorte. A principios de la década de 191930, el bruñido se usó por primera vez en una aplicación de alta producción: el bruñido de bielas por pilas.

Glossary of Honing Terms

Adaptador
A part used with certain mandrels to adapt them to fit the spindle chuck on the honing machine.
Buje de alineación
A concentric bushing used to minimize conical and parallel runout on machines with fully adjustable spindle noses.
Altered Stone
A standard honing stone, which has been shortened or otherwise changed for a specific application.
Óxido de aluminio
A man-made abrasive most often used in honing soft and medium hard steel. Designated by the letter "A" in the Sunnen stone code. Example: K12-A57.
Barrel Shape
A condition where the extreme ends of a bore are smaller in diameter than the middle.
Example of Barrel Shape
Bellmouth
A condition where the extreme end or ends of a bore are larger in diameter than the middle.
Example of bellmouth
Blind Hole
A bore that is constricted or closed at one end.
Example of blind hole contrictedor Example of blind hole closed
Bond
The material that holds the abrasive grains together in a honing stone. Conventional Abrasives use fused clay or glass and are know as Vitrified bonded stones. Superabrasive stones use a metal bond, resinoid bond, or a vitrified bond.
CBN
A man-made abrasive (cubic boron nitride) especially useful for honing the tough alloy steels and other abrasive resistant materials. Designated by the letter "N" in the Sunnen stone code. Example: P28-NM55.
Corcho adhesivo
A bonding material composed of powdered cork and phenolic resin. Cork bonded honing stones are used where extremely fine surface finished is required. (Best results are achieved when used with bronze guide shoes.)
Deburring
A honing process used to remove burrs, sharp edges or similar materials from rough bores.
Diamante
A very hard abrasive grain, which is essential to the honing of carbide, glass and ceramic materials. Designated by the letter "D" in  the Sunnen stone code. Example: K8-DV57
Diamond Dresser
A diamond abrasive used to dress honing stones other than Borazon or diamond.
Fijación
A method used to hold the workpiece while honing. Suggestions on different fixturing methods can be found in Data Files #107, 108, and 109.
Glazed Stone
A stone with cutting action impaired because the abrasive particles failed to break out of the bond when the cutting edges wore off. This condition shows up when the bond is too hard.
Zapatas guía
A part of the honing unit that stabilizes the bore being honed on the tool.
Dureza
As applied to a honing stone, describes the strength of the bond that holds the abrasive grains longer; a soft bond will permit the stone to “break down” faster, exposing new sharp abrasive grains.
Hard-Tip Stone
A honing stone having a tip or end of harder abrasive than the body of the stone. Used for honing blind holes where relief cannot be provided.
Hard-Tip Stones
Used primarily for blind hole applications, the tip of the stone is engineered to be more wear-resistent than rest of the stone.
Bruñido
An abrasive machining process primarily used for stock removal, precision sizing, and surfaces. It is characterized by the use of a self-sharpening abrasive stone, a relatively large area of contact with the work, and relatively low cutting speeds.
Honing Length
The actual length of the surface being honed.
Piedra de bruñir
An abrasive stick consisting of thousands of small abrasive grains bonded together.
Honing Unit
A complete honing tool consisting of an adapter (if required), a mandrel and wedge, stone(s), guide shoes, truing sleeve, and stone retainer or tension block.
Loaded Stone
A honing stone with cutting action impaired due to the cutting surface being partially covered with a foreign material, usually the material being honed. This condition is sometimes encountered when honing soft materials.
Mandril
The part of a honing unit which holds and positions the honing stone and guide shoes in their correct relative positions.
Metal Bond
A powdered metal bond often used with diamond or Borazon abrasives. Designated by the letter "M" in the Sunnen stone code. Example: P28-NM55.
Overstroke
The distance that the workpiece is stroked beyond the end of the stone. This distance is generally one-third the length of the stone (or of the part, whichever is the shortest).
Rainbow (or bow)
Sometimes called camber or banana shape. A condition where a bore's diameter may be the same over its full length but whose axis or center-line is curved. Correction of rainbow by honing requires a mandrel in which the stone and guide show length is at least 1-1/2 times the length of the bore.
Example of rainbow
Relief
An enlargement of diameter at the bottom of a blind hole which makes it possible for the end of the honing stone to pass beyond the bottom end of the surface being hones.
Runout
Off-center rotation of the honing unit which causes eccentric motion of the workpiece.
Carburo de silicio
A man-made abrasive most often used for stock removal in materials such as cast iron, brass, bronze or aluminum. Also used for fine finishes in all materials. Designated by the letter "J" in the Sunnen stone code. Example: K12-J47.
Stacking
A technique for honing short parts. Faces of the parts must be square with the bore prior to honing. A holding fixture is necessary for aligning and holding the parts on a common center.
Example of stacking
Taper
A bore condition where the diameter of a bore gradually increases from one end of the bore to the other.
Example of taper
Mango de alineación
A cylinder or workpiece whose purpose is to make the guide shoes and stone straight and parallel to each other, and radiused to the approximate diameter to be honed.
Waviness
A longitudinal wave, series of waves or ripple in a bore surface.
Example of waviness

Honing Technical Guides

This repository of technical resources provides an in-depth exploration of various honing techniques and invaluable insights to those seeking to hone their craft.