{"id":22186,"date":"2023-09-01T11:15:30","date_gmt":"2023-09-01T03:15:30","guid":{"rendered":"https:\/\/www.meetyoucarbide.com\/?p=22186"},"modified":"2023-09-01T11:16:27","modified_gmt":"2023-09-01T03:16:27","slug":"how-to-select-a-good-form-milling-cutters","status":"publish","type":"post","link":"https:\/\/www.meetyoucarbide.com\/es\/how-to-select-a-good-form-milling-cutters\/","title":{"rendered":"\u00bfC\u00f3mo seleccionar unas fresas de buena forma?"},"content":{"rendered":"
A form milling cutter is a specialized cutting tool used for machining complex contoured components such as various gears, crankshafts, camshafts, etc. It can replicate the external shape of the part and create the same profile through machining. Unlike traditional diamond or square insert tools, a form turning tool employs form inserts. Some form turning tools can be fed directly into the workpiece, similar to a drill bit, to cut into the material. For example, an end mill-type form milling cutter can cut in this manner, provided there is sufficient clearance left by the tool manufacturer at the tool’s end. Also, modular form milling cutters can be fed directly into the workpiece, but they consume a significant amount of power during the machining process.<\/p>\n

Si bien las herramientas de torneado de formas no pueden reemplazar a las brocas debido al \u00e1rea de compromiso m\u00e1s grande involucrada en la perforaci\u00f3n, que excede las capacidades de profundidad de corte de dichas herramientas, la capacidad de las fresas de formas de cortar directamente la pieza de trabajo resuelve un problema problem\u00e1tico en el mecanizado: la necesidad de perforar previamente un orificio inicial antes del mecanizado en bruto.<\/p>\n

Dado que las herramientas de torneado convencionales no pueden cortar directamente el material a lo largo del eje Z, es necesario perforar previamente un orificio de inicio. Otro enfoque consiste en utilizar una entrada inclinada, que a menudo requiere la aplicaci\u00f3n de software CAM. Sin embargo, con el uso de herramientas de torneado de formas, este paso se puede eliminar.<\/p>\n

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Caracter\u00edsticas de las fresas de formas<\/h1>\n

El fresado de formas implica el uso de herramientas de corte equipadas con insertos indexables que tienen filos de corte circulares. Estas fresas vienen con filos de corte circulares completos (usados para fresas de cara circular o fresas de punta esf\u00e9rica) o filos de corte circulares parciales. Las fresas de formas se clasifican en fresas modulares, fresas con v\u00e1stagos helicoidales y fresas modulares (helicoidales). Las fresas de formas utilizan herramientas de torneado de formas, lo que les permite tener varias ventajas, incluyendo un peque\u00f1o empalme posterior, altas velocidades de avance, que sirven como complemento a la tendencia del mecanizado de alta velocidad. Las fresas de formas tienen las siguientes caracter\u00edsticas:<\/p>\n

Fuerte capacidad de alimentaci\u00f3n<\/b><\/strong><\/h2>\n

Algunas fresas de forma pueden introducirse directamente en la pieza de trabajo, de forma similar a un taladro, para cortarla.<\/p>\n

Interpolaci\u00f3n helicoidal<\/b><\/strong><\/h2>\n

Al combinar fresas de forma con interpolaci\u00f3n helicoidal, resulta f\u00e1cil y r\u00e1pido mecanizar agujeros de gran di\u00e1metro.<\/p>\n

Mayor resistencia del filo de corte<\/b><\/strong><\/h2>\n

Debido a la ausencia de esquinas agudas, las herramientas de torneado de formas pueden tolerar mayores desviaciones de herramienta y vibraciones. Esto permite mayores velocidades de husillo y velocidades de avance durante el mecanizado, al tiempo que reduce el riesgo de rotura de la herramienta.<\/p>\n

N\u00famero de filos de corte<\/b><\/strong><\/h2>\n

Las herramientas de torneado de formas tienen m\u00e1s filos de corte disponibles. Seg\u00fan el tama\u00f1o del inserto y el acoplamiento posterior, las herramientas de torneado de formas pueden tener entre 4 y 8 posiciones indexables efectivas, lo que da como resultado una tasa de eliminaci\u00f3n de material al menos dos veces mayor en comparaci\u00f3n con los insertos de diamante y cuadrados convencionales. Esta ventaja reduce la necesidad de cambios de herramientas, lo que genera una mayor eficiencia y rentabilidad.<\/p>\n

Corte eficiente<\/b><\/strong><\/h2>\n

El uso de herramientas de torneado de formas permite alcanzar velocidades de corte tecnol\u00f3gicas elevadas sin requerir una potencia de m\u00e1quina extremadamente alta. Debido a su resistencia, las herramientas de torneado de formas pueden admitir velocidades de avance m\u00e1s altas para el mecanizado en comparaci\u00f3n con las herramientas de fresado de extremos cuadrados, e incluso pueden realizar desbaste pesado en m\u00e1quinas livianas.<\/p>\n

Acabado superficial superior despu\u00e9s del desbaste<\/b><\/strong><\/h2>\n

Las superficies fresadas con herramientas de torneado de formas presentan menos irregularidades perceptibles en comparaci\u00f3n con las superficies desbastadas con herramientas de punta cuadrada. La altura residual de las irregularidades de la superficie es menor. Las piezas de trabajo que se someten a desbaste con herramientas de torneado de formas tienen un acabado superficial superior, lo que les permite pasar directamente al mecanizado de semiacabado.<\/p>\n

 <\/p>\n

Aplicaciones de las fresas de formas<\/h1>\n

Elecci\u00f3n de las etapas de mecanizado: el desbaste se lleva a cabo normalmente utilizando fresas de forma (mostradas en la imagen superior), mientras que el acabado implica el uso de fresas de punta esf\u00e9rica de carburo s\u00f3lido (mostradas en la imagen inferior).<\/p>\n

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Using form milling cutters for roughing provides a better “preparation” for semi-finishing or finishing operations. When roughing is performed with square-end milling tools, there is a step left when cutting downwards. The larger the cutting depth per pass, the more pronounced this step effect becomes. Such uneven surfaces on the workpiece can result in uneven tool forces during semi-finishing, causing tool impact and deformation. This makes a direct transition from roughing to finishing impractical. Not only is semi-finishing necessary, but multiple finishing passes are also required.<\/p>\n

The use of form milling cutters greatly reduces the occurrence of the aforementioned issues. Instead of leaving a step like square-end tools, there are only small “wrinkles” with very low height that can be easily machined away. Form milling cutters are an optimal choice, especially for small cutting depths, where the height of these “wrinkles” is minimized. The surface of the workpiece after roughing is relatively smooth, allowing for easy semi-finishing. In some cases, it might even be possible to proceed directly to finishing.<\/p>\n

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Selecci\u00f3n de fresas de formas<\/h1>\n

1<\/b><\/strong>Elecci\u00f3n de la geometr\u00eda del inserto<\/b><\/strong><\/h2>\n

When machining a complex part, the fundamental requirement is that the cutting edge can access the regions corresponding to the part’s contours. This necessitates selecting the appropriate insert shape, main rake angle, secondary rake angle, front angle, and back angle. When choosing the insert shape, it’s essential to consider the insert’s strength. Circular inserts generally have the highest strength. For non-circular inserts, a larger nose angle increases their strength. Due to clearance angle considerations, form milling typically employs 35\u00b0 or 55\u00b0 diamond inserts. The choice of insert holder depends on the required cutting path. For intricate form milling, a J-type holder with diamond inserts can be chosen to achieve a larger back angle.<\/p>\n

2<\/b><\/strong>Insertar \u00e1ngulo trasero<\/b><\/strong><\/h2>\n

The main and secondary rake angles of the insert determine the back angle between the insert’s back surface and the workpiece. Different materials require different back angles. For instance, when machining tough materials, especially nickel-based alloys, there is significant springback. These alloys tend to deform ahead of the cutting edge and spring back after cutting. This springback causes the workpiece to scrape against the insert’s back surface, generating substantial cutting heat. Additionally, the work hardening of nickel-based materials produces cutting heat, leading to tool thermal failure. The failure mode might be tool chipping, but thermal expansion of the cutting edge results in tool fracture.<\/p>\n

Titanium materials can spring back by 0.05mm to 0.08mm, which necessitates a back angle of 14\u00b0 or 15\u00b0 between the insert’s back surface and the workpiece to prevent thermal failure when machining such materials. However, titanium and plastics have similar springback characteristics. Using an insufficient back angle when machining titanium can lead to tool thermal failure. Such a tool, when used for plastics, would generate cutting forces and heat due to springback, melting the plastic workpiece. The insert’s back angle shouldn’t be too large, as excessive back angle reduces insert strength. Inserts without a back angle have sufficient strength but must be mounted on a holder with a negative rake angle to create an adequate back angle. Using an insert with a positive rake angle and no back angle groove ensures the required insert strength while maintaining a positive rake angle cutting.<\/p>\n

3<\/b><\/strong>Fuerza de corte y control de viruta<\/b><\/strong><\/h2>\n

Los cambios en la relaci\u00f3n entre la pieza de trabajo, la herramienta y otros factores dentro del sistema de mecanizado afectar\u00e1n el control efectivo de la viruta. Por ejemplo, en el fresado de formas, a medida que la plaquita se mueve hacia afuera desde el centro de la pieza de trabajo, el espesor de la viruta disminuye, la profundidad de corte aumenta y el control de la viruta empeora. Una soluci\u00f3n es dividir una sola pasada en dos, cambiando el avance hacia afuera por uno hacia adentro para lograr el contorno final.<\/p>\n

Thin-walled and elongated parts are difficult to clamp, and cutting forces can cause workpiece deformation, poor surface finish, or even part scrapping. A specialized insert designed to control chips can minimize such deformation. If the machinability of the workpiece material complicates turning operations, parts made of two different materials can double this complexity. Therefore, when machining parts composed of multiple materials, one approach is to select insert grades capable of machining different materials. For example, when machining a part with an inner 4340 steel and an outer nickel-based alloy, the programmer must insert a pause to change the insert. To address this, using two different insert grades is recommended. When tool life remains low for both insert grades, Sumitomo Electric Industries’ AC2000 CVD-coated inserts from Japan can be used. By adjusting the feed rate and cutting speed, both materials can be machined without changing inserts, significantly increasing tool life.<\/p><\/div>\n

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A form milling cutter is a specialized cutting tool used for machining complex contoured components such as various gears, crankshafts, camshafts, etc. It can replicate the external shape of the part and create the same profile through machining. Unlike traditional diamond or square insert tools, a form turning tool employs form inserts. Some form turning…<\/p>","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[92],"tags":[],"class_list":["post-22186","post","type-post","status-publish","format-standard","hentry","category-cutting-tools-weekly"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.meetyoucarbide.com\/es\/wp-json\/wp\/v2\/posts\/22186","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.meetyoucarbide.com\/es\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.meetyoucarbide.com\/es\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.meetyoucarbide.com\/es\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.meetyoucarbide.com\/es\/wp-json\/wp\/v2\/comments?post=22186"}],"version-history":[{"count":0,"href":"https:\/\/www.meetyoucarbide.com\/es\/wp-json\/wp\/v2\/posts\/22186\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.meetyoucarbide.com\/es\/wp-json\/wp\/v2\/media?parent=22186"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.meetyoucarbide.com\/es\/wp-json\/wp\/v2\/categories?post=22186"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.meetyoucarbide.com\/es\/wp-json\/wp\/v2\/tags?post=22186"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}