It refers to the chipping characteristics of the plastic. Plastics, similarly, can behave differently–hard plastics as a name is a bit of a misnomer (though it is the industry standard in tooling catalogs). They have to do for example with the behavior of the sap relative to the sawdust and how the chips are made. It turns out that the characteristics that affect the feeds and speeds for wood are different than hardness. Mild steel is 120, hardened steel is 900, and tungsten carbide is 4000! Red Oak, for example, has a Brinell Hardness of about 3.7. Even Carbide is not all that much harder than hardened steel whereas it is phenomenally harder than even the hardest woods. What determines the “Size” of a Sweet Spot?Ī lot of this is all up to that relative difference in hardness between material and cutter. “Size” of Sweet Spot refers to how wide a range of numbers are safe. Imagine there are actual numbers on our Sweet Spot diagram. For harder steels and difficult materials like Titanium, the sweet spot gets very small indeed. In general, the sweet spots for woods are much larger than for metals. You can learn all this and much more from our free Feeds and Speeds Tutorial, but for now, let’s stay with this idea of a Sweet Spot. But, over heating and chip loading are the two main tool life enemies that are directly feeds and speeds related. This destroys a tool suddenly and is more commonly what beginners see.Ī lot else can shorten a tools life–chipped edges in some materials, materials like stainless steel can “work harden” and suddenly become much harder during the cutting process, and some materials like aluminum try to weld themselves to the cutting edge if lubricant or appropriate tool coatings are not used. – Tools can break because the flutes get too full, the chips have no place to go, and the tool jams and snaps off. This destroys a tool gradually, though gradual can mean a matter of minutes if the tool is hot enough. Running too slowly relative to feeds also generates a lot of heat due to Rubbing. Tools have a certain maximum speed, called the “Surface Speed” that governs how fast they can run against a given material. – They get too hot, which softens the tool and results in a dull edge. Tools usually fail for a couple of main reasons: It’s important to note you can get into just as much trouble running too slowly (due to rubbing) as running too quickly. You can optimize MRR (Material Removal Rate), Surface Finish, and to an extent a blend of all three. The green areas reflect ideal Sweet Spot matches for a material and cutting conditions. A typical Sweet Spot looks like this schematically: The Sweet Spot determines how the relationship between speed (spindle rpm) and feedrate need to come together for good cutting results. After all, there are so many categories for steel, why not for wood too? The answer has to do with the size of the “sweet spot” that relates feeds and speeds to good results in a material, together with the relative hardness of the woods (or other materials) versus the cutters (HSS or Carbide). People wonder why we don’t have a lot more categories and sub-categories. To access the full variety of woods under each family, use the "More." button on G-Wizard. You can see them in our G-Wizard Feed and Speed Calculator's Material menu: When calculating feeds and speeds for wood, we generally look at 4 different famillies. Here's your comprehensive guide to Feeds and Speeds for Wood, together with Tips and Techniques that are specific to cutting wood on a CNC Machine.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |