CNC Router Essentials. Randy Johnson

Чтение книги онлайн.

      

      CNC Router Essentials

       Design Essentials : 2

      if the sign wasn’t CNC cut, study its layout and shape and then use those elements in your designs. If you see something you like, whether it’s painted, hand carved, laser engraved, or molded, grab the idea and archive it.

      Think outside the box

      As you look for ideas, don’t discount anything as a possibility. When you’re new to CNC, it’s easy to look at something and think it’s too hard. But as your skills increase, you’ll want to have more challenging projects. If you like it, capture it, and then figure out later how to execute it.

      Keep your ideas organized

      With today’s smartphones and tablets, and the fluid nature of the Internet, it’s easy to grab ideas no maer where you are. Maybe too easy, since it makes keeping all these files organized a challenge. There are many approaches to this with today’s technology. At a minimum, keep your ideas organized by category so you can find them as your collection grows deeper and deeper.

      From inception to completion, you can let your creative juices flow with CNC work. Keep in mind that, in addition to wood, CNC machines can cut aluminum, brass, bronze, foam, and a variety of other materials. Start stockpiling those ideas!

      size because an .stl shape is a wire mesh. As you scale up the model, the mesh becomes visible as flat triangular facets, which will also be visible in the final carving. The best defense against this is to use a high-resolution .stl designed for CNC design work and preview the .stl in the CAD/CAM soware before commiing it to your design.

      Project inspiration

      Where can you find project ideas? Well, a simple web search or a visit to Pinterest or Instagram will reveal thousands of pictures of CNC work. A lile more searching will reveal sites with ready-to-machine CNC project plans—some for sale and some for free. Aer you get some experience, lots of existing DIY shop projects (wood, plastic, aluminum) can be converted to CNC projects. It’s a great idea to network with other CNC owners: join a forum or a user group. Some of these groups hold meetings with show-and-tell time, providing a close-up look at completed CNC projects and the opportunity to ask questions about how the person made them.

      Signs

      Making signs is an immensely popular application of CNC machines and an excellent way to gain some experience at CNC project design and machining. Plus, existing signs are all around and can be a rich source of inspiration. You will learn a lot about sign design by just looking at existing signs in your neighborhood. Even

      CHAPTER 

      Toolpath

      Essentials

      Once you draw a project in CAD, you then create toolpaths tocut the project. Seing up a toolpath requires a number of steps, but none are difficult or involve writing code. Plan to practice the steps virtually in soware a few times before making test cuts on your machine. In this chapter,you’ll learn about:

      • Router bits for CNC

      • Four frequently used toolpaths

      • The importance of chip load

      • Determining the best feeds and speeds

      • The primary steps in seing up a toolpath

      CNC Router Essentials

      3 : Toolpath Essentials

      rather than liing it, which can occur with an upcut bit. Because a downcut bit pushes the chips down when cuing, the chips usually get packed into the kerf. The packed-in chips will fall away when you separate the finished parts. If you need to remove them before that, try running the cut a second time to loosen up the chips and then remove them with compressed air or a vacuum.

      Compression bits combine upcut and downcut shearing action in one bit and thus leave a clean cut on both the top and boom side of your material.

      Router bits

      Many of the bits you use with your handheld router or router table can be used in your CNC. There are also specialized bits for CNC that you will find useful. Carbide-tipped or solid carbide bits are the most commonly used bits on CNC routers because they stand up to abrasive materials such as MDF and plywood. However, due to their hardness, they are also more susceptible to breakage than high-speed steel (HSS). HSS also has the advantage of being less expensive than carbide, although HSS bits generally dull quicker.

      You probably already own a few straight bits. These are good general purpose bits, but won’t give you the cut quality of a spiral bit. Spiral bits are available as upcut, downcut, or a combination, Image 3.1. Upcut bits act like a drill bit, pulling chips up out of the cut, which keeps the cuing path clear. The spiral creates a shearing action that reduces chipping and gives you a beer edge quality on your material than a straight fluted bit. An upcut bit may fray or chip the top surface of your material, but when through cuing, it provides a chip-free cut on the boom side.

      Downcut spiral bits push down toward the material. This downward shear action provides chip-free cuing on the top surface but may cause chipping on the boom of some materials, such as melamine and plywood. Downcut spiral bits are also useful when cuing thin materials because the downcut pressure helps to hold the material against the bed

      A router bit starter set

      Image 3.1: Straight bits come in a variety of configurations. The four shown here are (left to right): straight flute, upcut spiral end mill, downcut spiral end mill, and compression end mill.

      • 60 and 90° V-bits (V-carving) • "-, "-, and "-diameter upcut СКАЧАТЬ