Roland HIGH-Z-S 1000 CNC Machine The Software and CNC Machine User Guide Ålesund 2016
Introduction CNC - Computer Numerical Control - Refers to the use of a computer to control and monitor the movements of a machine. The machine can be a milling machine, lathe, router, welder, grinder, laser or waterjet cutter, sheet metal stamping machine, robot, or many other types of machines. For larger industrial machines, the computer is generally an on-board dedicated controller. But for more hobbyist types of machines, or with some retrofits, the computer can be an external PC. The CNC controller works together with a series of motors and drive components to move the machine axes in a controlled way, executing the programmed motions. On the industrial machines there is usually a sophisticated feedback system that constantly monitors and adjusts the cutter's speed and position. The CNC-machine at the FabLab are capable of routing, milling, drilling, engraving and sculpting in a variety of materials such as: MDF, modeling wax/resins, foams, plastics (PVC, plexiglass). Aluminium, Brass, Copper and sheet steel. The CNC-machine can also produce foils and vinyl for stencils or sign art. It can mill printed circuit boards and create panels and enclosures for prototypes. Some samples of what can be made with the CNC-machine: 2
Operating the CNC machine This manual contains just the minimum of information required to safely operate the CNC-machine. Every operator of the FabLab CNC-machine should read this operating manual and try one or more sample project prior to learn how the system works. It is important to get to know the equipment because there are real chances of injuries and damage to the CNC-machine, if not operated correctly. Technical specification Machine Working Area: X=1000 mm; Y=600 mm; Z= 110 mm Table size/clamping area: 1330 x 700 mm Total dimensions incl. motors: LxWxH = appr. 1350x840x500mm Traverse rapid feed max. 12000 mm/min Working feed max. 8000 mm/min Resolution 0.00187 mm ( 1/8 Step) Repeatability approx 0.02 mm Reference switches on all axes with software limit control Double safety emergency stop button Milling Motor anchorage: Euroneck 43mm How does it work? A CNC-machine is part hardware, and part software. The hardware (see figure) consist of a bed where the workpiece is mounted and several rails (X, Y and Z direction) that guides the tool to the desired position. The tool (normally called a bit) is connected to a collet and mounted to a router. The tools/bits come in a number of shapes and lengths, depending on the workpiece material and application. The CNC-machine is connected to a piece of electronics called a controller (see figure). The 3
controller tells the CNC-machine what to do, like move to a certain position, and move at a given speed. The controller in turn, receive its commands from a piece of software called a postprocessor. The postprocessor is unique for each controller model. The task of the postprocessor is to process G-code or ISO code, which is a simple alphanumeric programming language developed for the earliest CNC machines in the 70 s. In our case the postprocessor is a executed from a software called WinPC NC on a pc that is connected to the controller via a special USB interface. To make a part on the CNC machine, a file containing its G-code is loaded into WinPC NC, which in turn executes the G-code. It is possible to write G-code in a text editor and send it to the CNC-machine, but normally it is much easier to create parts using a dedicated modelling software like VCarve Pro. There are several ways to create parts with a CNC-machine, and the term toolpath is often used to describe what kind of process is going on. A definition of a toolpath is: The path through space that the tip of a cutting tool follows on its way to producing the desired geometry of the workpiece. Different software have different capabilities, and will produce many different toolpaths. Most common are the 2D, 2.5D and 3D toolpaths. The definitions of 2D, 2.5D and 3D toolpaths can be a bit vague and can appear to overlap. 2D toolpath A 2D toolpath, cuts are made to the same depth, and the walls inside the cuts are straight. These toolpaths are made with Endmill bits: 4
An end mill is distinguished from the drill bit in its application, geometry, and manufacture. While a drill bit can only cut in the axial direction, a milling bit can generally cut in all directions, though some cannot cut axially. 2.5D toolpath A 2.5D toolpath is a bit more complex to describe. 2.5D milling toolpaths machine only in the XY plane. The Z axis is used only to position the tool at depth. The move to the cutting plane is a straight down feed, rapid, ramp or helical feed move. If the walls from a cut are bevelled from the use of V-bits it is usually considered 2.5D. A typical V-bit: For both 2D and 2.5D toolpaths, one usually starts with a 2D vector drawing, or text. Data can be imported from a huge range of design programs using a variety of industry standard file formats. These include DXF, EPS, AI as well as PDF files (if they contain vector data). 3D toolpath The most complex (and time consuming) parts are made using a 3D toolpath. 3D toolpaths are used to machine parts that are more freeform- they may have not have any perfectly vertical or horizontal surfaces. A part made for 3D toolpath is usually created in CAD programs like Siemens NX, Rhino, SolidWorks, AutoCAD Inventor, Silo, MOI, Blender, SketchUp etc. 5
For 3D toolpaths the bit that is used is most of the time is called a ball-nose end mill : With 3D toolpaths you can make reliefs, surfaces, text, etc. You have more freedom, but the parts usually take longer time to complete. Other toolpaths Pocket toolpath: Consider using a roughing end mill to remove most of the material. These serrated mills can remove material at a far faster rate than finish end mills. They do leave a poor finish on the floors and walls that must be finished with a separate finish tool and operation. Modelling Depending on what type of part you wish to create, there exist a myriad of software to do the job. We have at our disposal a modelling software called Vectric VCarve Pro (http://www.vectric.com/products/vcarve.htm) that is suitable to create 2D and 2.5D toolpaths from scratch. If you are familiar with designing in another software, it is no problem. You can easily import 2D-vectors from other software. When you have finished your basic design, VCarve Pro will export the necessary G- code for the CNC-machine. One of the benefits of using VCarve Pro is that you can visually see how the toolpaths are implemented on your workpiece through an animation. The program will also estimate how long a certain toolpath will take to complete. It is very useful to know how long a given toolpath is going to take. If a certain toolpath is going to take very long time to complete, you can often make adjustments such as increase feed rate and change the given tool. A larger tool will 6
always be able to finish the job quicker than a smaller one, but usually the finish will be better with a smaller tool. If you are going to make 3D toolpaths you can import your 3D parts into VCarve Pro as long as the file format is compatible with VCarve Pro(STL, OBJ, 3DM, etc). You can use any CAD software like Siemens NX, Autodesk Inventor, SolidWorks, etc., to create your 3D model, as long as they can export to one of the compatible formats. After the model are imported and placed on your workpiece to your requirements, VCarve Pro will generate and export G-code for the CNCmachine. Milling a part When you have finished modelling a part and created the toolpath(s) in VCarve, it is time to produce the part. To produce a part on the CNC-machine, this flow-chart can be used as a simple guide: There are so many ways to operate a CNC machine, so these steps will necessarily be general, but are valid for most of the uses. Safety CNC work has the potential for both short term and long term safety issues. The potential short term issues are obvious: A powerful machine not under your direct control moving a sharp cutting edge spinning at 1000 s of revolutions per minute if something goes wrong it can happen fast. Always protect yourself by wearing appropriate safety glasses and following accepted rules for working around rotating equipment. Clamped tools such as milling spindles can lead to severe personal injury or material damage. Never touch moving tool during operating process! Before exchanging tools, always pull power plug of the milling motor or turn off the machine and secure against restarting. In CNC, a "crash" occurs when the machine moves in such a way that is harmful to the machine, tools, or parts being machined, sometimes resulting in bending or breakage of cutting tools, accessory clamps, vises, and fixtures, or causing damage to the machine itself by bending guide rails, breaking drive screws, or causing structural components to crack or deform under strain. A mild crash may not damage the machine or tools, but may damage the part being machined so that it must be scrapped. 7
enjoy your result and continue to be creative! 8