• Mit FabLab Instructor Who? Loves Architecture Making/DIY New Trends and Tendencies Sport and relaxing Loves meeting new people Learning Openminded How? ASK EVERYTHING ! ! ! ! ALWAYS PLEASED TO ANSWER JUST STOP ME ! SERIUSLY ASK ! ! ! LETS MAKE IT FUN ! ! ! ! woooo hoooo ! ! ! LETS KNOW EACH OTHER (INTRODUCE YOURSELF) IF you don´t understand my awfull ENGLISH I can repeat or say it in FRENCH or SPANISH Learning has to be funny not boring, nobody evaluates nothing ! ! !
AUTOCAD FIRST STEPS HOW TO SAVE TIME ! TYPES AND HOW IT WORKS LETS ENJOY DESIGN SOME THINGS DESIGNS/WHAT WE CAN DO IF WE GO FAST WE CAN ALSO USE THE SMALL ONES ! ! ! 1-2 day 3-4 day SAFETY (HOW TO TAKE CARE OF YOU AND THE MACHINES) FINISH THE DESIGNS HOW SHOPBOT WORKS ! LET´S SET THE MACHINE AND LEARNING HOW TO OPERATE HAVE FUN CUTTING ! ! ! ! ENJOY YOUR DESING 7-10PM 7-10PM
CONVERTS TEHE DESIGN PRODUCED BY COMPUTER AIDED DESIGN SOFTWARE (CAD) INTO NUMBER. THE NUMBERS CAN BE CONSIDERED TO BE COORDINATES OF A GRAPH AND THEY CONTROL THE MOVEMENT OF THE CUTTER. IN THIS WAY THE COMPUTER CONTROLS THE CUTTING AND SHAPING OF THE MATERIAL
GIVE LONGRADIO COMMUNICATION ON ISOLATED AREAS WITH LOW RESOURCES ADAPTING A WIFI ROUTER WITH A CNC STRUCTURE THEY CAN COMMUNICATE BETWEEN VILLAGES MILES AWAY
of square light on one side and a rotated checkerboard on the other. The torqued geometries allows light to be transmitted not only through the thin end plane, but also through the edges of each tunnel.
out a pattern of nested torqued tunnels of light. A square geometry is twisted 45 degrees as it is extruded from the base foam. This is done on both sides, but with a 45 degree difference.
is consistent and accurate work pieces. todays CnC machines feature a typical accuracy rate in the range of 2 to 4 thousandths of an inch or 0.05 to 0.10 mm and repeatability near or better his means that once a program is verified, two, ten, or one thousand identical work pieces can be easily produced with the same precision and consistency
programs, running a different work piece is as easy as loading a different program. the resulting reduction in the number of machines needed in a wood manufacturing shop is yet another benefit worthy of noting Less Work-in-Progress (WiP) also translates into lower inventory and less investment in non value-added resources.
usually platforms that allow a computer-driven cutting tool to carve a material in all three dimensions. • CNC routers can be programmed to make precise, repeatable cuts on flat or low-elevation wood or plastic projects, while CNC mills turn blocks of steel or other materials into engine components, brackets, and other incredible metal creations. The CnC machine takes no breaks and although the human operator does, he can prepare work for the machine to perform on its own while he is undertaking other work.
with a collet. A collet is designed to hold a bit with much more force than a typical drill chuckcollets for high end tools (spindles) are designed to be switched (changed) rapidly, some even have with ATC (automatic tool changers) Caution! Keep collets clean, a piece of debris or dust between the collet and bit can cause the bit to spin elliptically, harming bit, part or even operate anormaly
water compresor and bigger rooms • DIRTY-the coolant gets everywhere • POWERFULL-can cut metal and strong materials • CHEAP-less parts machinery • CLEAN-with a dust collector no need to clean everything • WEAK-can cut,wood,foam, plastic,softcomposites and soft metals with manual lubbing
As often as we’re reminded, everyone neglects one of the main workshop rules: Maintain your tools. This is crucial when it comes to CNC machines. If the CNC isn’t calibrated or is out of square, the output won’t match the input, no matter how long you’ve pored over the plans. • It’s very important to use an end mill that is specified for the particular material you are using, “There are end mills specific for wood, plastic, aluminum, steel, and so on.”
Drill bits are designed to plunge directly into material, cutting axially and creating cylindrical holes. End mills are typically used for horizontal carving and cut laterally.
flutes that extend to the end face and enable plunge cutting. To minimize tool breakage and stress on the material being cut, most CNC software will “ramp” the end mill slowly into lateral cuts.. Additionally, most mills are “center-cutting,” meaning they are able to cut both axially and laterally. DRILLS ARE NOT END MILLS!
to side/horizontal cutting while bits with more flutes are better suited to end milling • Side cutting generally requires larger amount of material to be removed and the bits with fewer flutes allow the swawf to evacuate with less restriction. TIPS
mills (great for hardwood and plywood) • 2 or 4 flute ballnose mill (great for 3D contours) • Single or “O” flute mill (great for plastics like HDPE and acrylic) • 60° or 90° v-bit (great for cutting hardwood signs)
mill tip shape is designed for a particular purpose. Some common cutter shapes are ballnose, fish tail, surface planing, v‐carving, and straight. V‐bits produce a “V” shaped pass and are used for engraving, particularly for making signs. Ballnose mills produce a rounded pass and are ideal for 3D contour work Fish tail cutters will produce a flat surface
want a ball nose bit that is appropriately sized for the level of detail in your model. Ballnose (aka contouring) bits are fantastic for 3d carving Ballnose Cutter
you’ll need to get a v bit They are available in many sizes and angles. The most common and useful angles in order are 60deg, 90deg, and 30deg. V - Cutter
for maintaining the spoil board on your CNC router, you’ll want to have a spoil board cutter or flycutter bit. These bits are made to skim the surface and leave a smooth flat finish Spoil Board Cutter
speed with edge finish Choose the appropriate bit direction (The biggest decision you’ll need to make when picking your bit is cut direction. Your choice are uncut, downcut, and compression (a combination of upcut and downcut)) TIPS BIGGER IS ”BETTER”
They are ideal for pieces that have been previously engraved or v-carved and cannot be flipped to hide tearout. In addition, as downcut mills pack the chips into the cut path, they can be used instead of tabs to hold down a workpiece and keep it from moving A CNC router spins a cutter clockwise. Upcut mills eject chips towards the top of the workpiece, producing a cleanly cut bottom surface. The downside is possible surface splintering or “tearout” on the top surface as the chips are ejected upwards.7
grooves that wrap around the sides of the end mill. Each flute has a single tooth with a sharp cutting edge (although there can be more than one) that runs along the edge of the flute. • As the tooth cuts into the wood, each flute whisks away a small section or “chip”. The fewer the flutes, the more material that is ejected with each tool rotation. The overall cutting depth should never exceed the length of the flutes on an end mill. If cutting deeper than the length of the flutes, the tops of the flutes will be blocked and chips won’t clear, building up heat and reducing tool life
cut by a specific tool type. More flutes create a smoother surface finish, while fewer flutes remove material fastest, but make rougher cuts. • Proper chipload is important because chips dissipate heat. Hot cutters can lead to suboptimal results, including burned wood, a poor edge finish and dull tooling.
removal • Up Spiral – great chip removal, can tear- out the top of thin veneer such as finish grade plywood • Down Spiral – poor chip removal, no tear out, slower feed rate • Compression – combination of up and down spiral, great all around bit, great for plywood or laminated sheet goods.
for end mills are HSS (High Speed Steel) and Carbide. Carbide is the harder of the two, will last longer and can handle faster feedrates. To make carbide even better, there are various coating material applied • The gold coating on the left is TiN. No, not the material of cola cans, but a very resilient material (Titanium Nitride) that can withstand higher heat and provides a bit more hardness. • : TiCN (Titanium Carconitride) which is great for various metals, TiAIN (Titanium Aluminum Nitride) which is even better for metals (not aluminum which is in the coating itself) • AITiN (Aluminum Titanium Nitride) with similar characteristics as TiAIN, • Diamond, but don't get this for your loved one, unless they need a tool. Don't use diamond on metals either, but this material coating is superior on other materials especially composites and graphite
Speed – rotational speed of the cutting tool in revolutions per min Spindle speed that is too fast paired with a slow feed rate can result in burning or melting. • Feed Rate – Surface speed at the center of the rotating tool Spindle speed that is too slow paired with a faster feed rate can result in dulling of the cutting edge, deflection of the end mill and possibility of breaking the end mill. • Step down – the distance in the z direction per pass that a cutting tool is plunged into the material • Step over – the maximum distance in the x/y direction that a cutting tool will engage with uncut material Using the incorrect feed rate can have some interesting consequences, besides a broken mill and a creaky, inaccurate CNC. Generally • Plywood Cuts Best At A Rate Of 80 Inches Per Minute (Ipm) And 0.4 Inches Depth • Acrylic Plexiglas Works Best At 130 Ipm, With 0.03 Inches Depth. If you run your machine too slow, you risk burning the material or gumming up the cutting tool with melted material. In the case of milling aluminum, it can turn the end mill into a solid rod … not very useful for cutting
minute) / (RPM x number of flutes) • cut depth: ~ tool diameter/2 • step-over: ~ tool diameter/2 “Use your ears too, the tool should sound good when cutting … trust your gut” Feed Rate / Speeds Golden Rules The shopbot software includes a calculator for feed rates. OR http://www.carbidedepot.com/formulas-milling.htm The mill should be warm, maybe a little hot to the touch, but it should not burn you. If it is too hot, increase the feed rate or lower the spindle speed
6.35mm Shank diameter - 1/4 inch or 6.35mm Excellent Quality on Top and Bottom Edges of Cut • Soft Wood, Soft Plywood, Laminate Chipboard and Laminated Plywood: Chip load: .015 to .017 Suggested Low End Feed Rate: 540 IPM Suggested High End Feed Rate: 612 IPM • Hard Wood and Hard Plywood: Chip Load: .014 to .016 Suggested Low End Feed Rate: 504 IPM Suggested High End Feed Rate: 576 IPM • MDF (Medium Density Fiberboard): Chip Load: .013 to .015 Suggested Low End Feed Rate: 468 IPM Suggested High End Feed Rate: 540 IPM • All Feed Rates are based on 18,000 Spindle RPM
direction of cut and rotation of the cutter combine to try to "suck" the mill up over • It produces the best surface finish • The width of the chip starts at maximum and decreases. • More power required.. CONVENTIONAL TWO TYPES OF CUTTING TWO DIFFERENTS RESULTS CLIMB • Upward forces are created that tend to lift the workpiece during face milling. • Conventional milling is preferred for rough surfaces. • The width of the chip starts from zero and increases as the cutter finishes slicing. • Less power required
diameter or less, you should definitely climb mill • Climbing to rough and conventional to finish • In case of cutting some types of foam CONVENTIONAL When to use each one¿ CLIMB • - When cutting from 3/4 to 1x the cutter diameter, you should prefer conventional milling. • conventional milling for the finish pass Up to 3/4 of the cutter diameter, it doesn't matter which way you cut. There is a problem with climb milling, which is that it can get into trouble with backlash if cutter forces are great enough. In general, CNC machines shouldn't have any noticeable backlash, so these are more concerns on manual machines.
or worse... • Use the shortest bit that will do the job...Less deflection, fewer broken bits • Don’t forget to turn the router on! • In the battle between router bits and clamps ... the clamp wins everytime! BURNED MILL ! ! ! BROKEN MILL ! ! ! BENDED MILL ! ! ! DESTROYED MILL ! ! !
or worse... CHIPPING CRATERWEAR FLANKWEAR DOC NOTCHING THERMALCRACKS BUILT UP EDGE • Cutting too slow will burn the bit or worse... • Cutting too slow will burn the bit or worse... • Cutting too slow will burn the bit or worse... • Cutting too slow will burn the bit or worse... • Cutting too slow will burn the bit or worse... IF WE LOOK CLOSELY WITH AN AUGMENTATION LENS…
a bit that’s “screaming” wants a greater chip load Just like you.... A router bit shouldn’t smoke, it’s bad for its health. A smoking bit wants a greater chip load Keep it clean... A bit with built up tree resins, tars and sap are susceptible to pitting form the acids in those compounds. A published chipload isn’t gospel...Start out with the recommended chipload and increase the feedrate until finish starts to deteriorate, then back off 10%. Now decrease the RPM and repeat the same steps. This process also works when you don’t know the manufacturers recommended chipload. Breakin’ em left and right... Even a properly used tool will occasionally break. If you are experiencing multiple tool failures, STOP and ask yourself, Is this the right tool geometry for this job? Is the collet clean and is the bit properly installed? Recheck
secure the work very well. Excessive vibrating of the material will generate additional heat and lead to premature bit failure or poor surface finish. It is also important however, not to overtighten the screws as they will cause bowing in the material that may effect the dimensional accuracy. Flat head screws are better than tapered head screws here. Hold Down
keep a part steady while being routed, many people insert holding tabs in the pattern. The tabs act as tiny bridges that hold the milled part to the stock material. The number of tabs depends on the part that you’re cutting. • There is a balance between using more tabs than necessary, and not enough,” • Not enough, and the tabs can snap during the milling process. More than necessary, and you waste much of your time breaking them away after the job is done.” • When holding tabs won’t do the job, use holding screws instead. Drill two or more holes into the part to be cut, and manually screw these holes to the spoil board (the sacrificial material supporting your project from underneath) before cutting around the perimeter of the object.
Cheap allows a lots of materials and fixations Always check the thickness of you material to don´t cut it to much When the are very used the Z is inaccurate SACRIFICE BOARD
ear protection and steel toed boots. Avoid loose‐fitting clothing or dangling jewelry. 2) Keep eyes, hands, hair and clothing away from the ShopBot and router when it is operating. Tie long hair back. Do not use your hands to hold down parts that may come loose as they are cut out. 3) Read and follow the safety information that comes with your router, bits and other accessories. Unplug or shut down power to the router or spindle when changing bits. 4) Listen for changes in sound that may indicate a problem while running the tool. ALWAYS be near enough to the Remote Stop Switch or Space Bar on the computer keyboard to be able to stop the gantries should a problem arise.
Inspect your bits for wear, burning, dullness and cracks each time you use them. •Choose a bit with the largest shank and the shortest bit length to fit the task to avoid excessive bit deflection and stress. • Never cut deeper than 1⁄2 mes the diameter of the bit in a single pass. Not only will two passes make a cleaner cut but a shallower cut will cause less bit deflection and danger of breakage. • Check your collets frequently. Collets do wear out, and a loose collet can result in greater deflection and shimmy which equal poorer quality cuts and greater chance of breakage. 6) Avoid unsafe holddown practices that can shatter a bit or allow parts to move during cutting. • Make sure that the vacuum is sufficient to hold down small parts. Create templates or use the tabbing feature to hold small parts in place until you are ready to remove the machined pieces. 7) Locate mechanical holddowns such as clamps or sheet rock screws well clear of the cutting area. Design your files in such manner that the bit does not encounter the screws or clamps. Countersink holes for holddown screws. 8) Air cut your file before you put actually cut the file using the 3D offset option. Remember to deselect the 3D offset when you are ready to really run the file.
when being cut 10) Set Z accurately before starting the cut file, and know exactly how thick the material is. 11) Plan your toolpaths so that you cut out details and small parts before cutting out the big parts and drill any holes in a file while the material is intact and positioned properly, then go back and cut out the pieces.
limits 2) Drilling into the support. 3) Breaking the cutter/the support 4) Too high feed rates 5) Forgotting to switch on the spindle 6) Forgotting to fix properly Only if I should have take more care…..
use your common sense and trust your gut. Every bit is a little different and there is a wide range of densities in solid wood and different sheet goods Experiment Safely Experiment Safely Experiment Safely HOW MANY TIMES DO I HAVE TO SAY?
-Cooling needed -Very hard and sharp chips ALUMINIUM -Relative hard -Need high power spindle -High friction-heat -Often lubrication/cooling needed -Low melting point – stick to cutter.
always rough Good for large objets Have to choose correctly compatible glue o coating (styrospray) EXTRUDED POLYSTYRENE -More expensive -Tougher / better surface -Very good for test runs -Smoother finish than expanded one
Polyurethane HOMI in Hongdae http://www.homi.co.kr/mall/index.php Brass small shops around here Machinable wax https://www.machinablewax.com/ Protoboard ‘raku‐tool’ http://www.ilbeom.co.kr/
Many shops is Incheon ‐ not many internet shops / naver can help Good online shop with much information: http://www.onlinemetals.com/ AND OF COURSE AROUND SEUN SANGGA ! ! ! !
edge, the end mill only cuts t material once along the shared edge. That saves you time and m also lengthens the lifespan of your end mill. Implement the principles of “lossless design” and lay each component as close to the other ones as possible. That is called ” N E S T I N G”
Clean: Provide clean drawings; delete all objects that are not cutting or engraving lines • Nest: Combine all parts of the same material on one sheet. Our maximum board size is 2400x1220mm (ShopbotPRSalpha96-48) . Try to make a good fit to save material usage. • Multiple sheets: Need more parts than you can fit on one sheet? Create a new drawing and place your remaining parts here. • No fills: Disable all fills and hatches. (except for area engraving) • Explode text: Create outlines for all text. This can be done with the "Explode" function in most CAD applications and the "Create Outlines" in Illustrator. • Thin lines: Choose a line thickness of 0.2mm or hairline.
see that the constraints of using CNC routers make clear that joints which are specifically designed or adapted to the process are the most suitable. TERMINOLOGY POCKET: a recess cut into a piece, usually to accommodate a mating part from the other member in the joint or to “ dig” on the material . CUT :is the most common on 2d cutting, it is just cutting like a laser cutter but with the cnc .
A slot (U shaped flat bottom cut) or channel made with the grain. DADO :A slot made across the grain. RABBET: A slot cut parallel to, and along the edge of, a board. Half-Lap or Lapped: A dado or groove is cut into each workpiece to half their thickness to allow the parts to overlap one another.
A projection on the end of a piece for insertion into a mortise. MORTISE :A cavity or hole in a workpiece, meant to receive a tenon. DOVETAIL: A joinery technique noted for its resistance to being pulled apart. This is an interlocking joint where an angled male part fits into a similarly shaped female pocket. BLIND JOINT: Refers to joinery with mating surfaces not protruding through the visible faces of the pieces being joined.
JOINT: A joint where one part protrudes through the other piece. THROUGH JOINT :A joint where the other members are visible on both sides. CATEGORISED IN : 1 EDGE TO EDGE JOINTS 3 HOUSING JOINTS 2 CORNER JOINTS 4 FRAME JOINTS
Laser cutters can cut much finer details because they have very small “kerf”. - On the other hand, they’re more expensive and can’t do partial-depth cutting or “pocketing” like a CNC router can. -They also use heat, which can burn the substrate and/or generate nasty off-gassing. On the other hand, the burning effect can be used decoratively. -A CNC router can change bits and cut complex relieved surfaces, or make cuts with mitered or otherwise profiled edges. KERF: ‐A GROOVE OR NOTCH MADE BY A CUTTING TOOL, SUCH AS A SAW OR AN AXE,ETC ‐THE WIDTH OF A GROOVE MADE BY A CUTTING TOOL
Because of its very small cutting channel, a laser cutter can produce an inside corner with a sharp angle, whereas a rotary cutter using a physical tool is limited to inside corners rounded at the cutting tool’s radius:
The laser-cut version, with its sharp 90 corners, is suitable for use in a simple edge-lap joint The router-cut version, however, doesn’t work. The radiused corners bump into each other and the part edges don’t line up. You can cut each slot a bit deeper, of course, and in some applications this may be OK, but doing so leaves a void in the center of the joint and concentrates stress on the radiused corners
average, this method offers the best compromise, IMHO: The flat areas between the divots seat against each other firmly and the divots themselves are concealed inside the joint. BUT YOUR TOOL HAS TO BE SMALL ENOUGH
in which two slotted members are “halved” into one another, is often referred to as an “edge lap.” In the basic edge lap, the slot’s width and the stock thickness are essentially the same, and the two joined members are disposed at right angles to one another. In THE OBLIQUE EDGE LAP, both slots are wider than the thickness of the stock, the resulting edge lap is “loose” or “wobbly,” and the joined members can be disposed at acute or obtuse angles to one another. In this configuration, the edges of the slots do not lie flush against the surface of the stock, and the joint will be unstable without the presence of at least one other member. Nonetheless, the oblique lap can be indispensable for breaking out of the “boxy” limitations imposed by using only basic ninety-degree edge laps.
CNC EDGE TO EDGE JOINTS LAPPED DOVETAIL: This example allows two boards to be joined along their edge. On the back side of the joint the edge is a straight line T o
CNC EDGE TO EDGE JOINTS DOUBLE LAPPED DOVETAIL: Double dovetails in this version. So the decorative tails appear on each side of the piece (as opposed to a straight line in the example above). T o
CNC EDGE TO EDGE JOINTS BOARD LENGTHENING WITH JIGSAW KEYS Joints such as the following two use removable keys to edge join the boards. In reality these keys are tough to get in and out of the pockets if the fit is good. So these are not suitable as knock‐down (take apart) joints. T o
CNC EDGE TO EDGE JOINTS BOARD LENGTHENING WITH ASYMMETRICAL DOVETAIL KEYS Another version using more traditionally shaped dovetails. Butterfly keys are similar to this although they are symmetrical about their centerline (these are asymmetric). T o
CNC EDGE TO EDGE JOINTS GOOSENECK MORTISE AND TENON JOINT The shape of this joint demonstrates the ease with which the CNC can cut complex curves into joinery. T o
CNC EDGE TO EDGE JOINTS HALVING WITH ELLIPTICAL TENON A halving joint is one where the two parts are each thinned by half and overlap one another. The ellipse tenon in this joint provides mechanical resistance to pulling apart. This joint would be weak in hardwood because the sheer plane is parallel to the wood fibers T o
CNC EDGE TO EDGE JOINTS TRIPLE DOVETAIL Single dovetail on one side, double on the other. Unlike the joint above these are not aligned laterally making it stronger. T o
CNC CORNER JOINTS FINGER TENONS These joints are the simplest of the CNC compatible tenons. The joint is fully exposed at the corner. There is a lot of surface area for glue T o
CNC CORNER JOINTS BLIND FINGER TENONS This example uses pockets along the edge of the joint to keep the tenons from showing through. This is referred to as a blind joint. The edges are visible from the outside making a nice detail to relieve the sharp edge T o
CNC CORNER JOINTS FINGERTIP TENONS Through corner joint. The two parts are identical. They provide a lot of glue surface area making for a very strong connection. Here the narrower tenons are referred to as "fingertip" rather than "finger" T o
CNC CORNER JOINTS FINGERTIP TENONS WITH KEY The lengthened tenons of this joint have a notch which accepts a key which secures the joint against tension. T o
CNC CORNER JOINTS CATCH TENON This is another break‐down joint. The parts are slid together and the catch is pushed through the matching latch. When through far enough the tenon flips down and hooks to secure the joint from coming apart by tension. T o
CNC CORNER JOINTS DOWELED MORTISE AND THROUGH TENON This example uses a dowel to prevent one part from sliding back through the other. When the dowel is tight against the face of the mating piece the joint is pretty solid. T o
CNC FRAME JOINTS OVAL SHOULDERED HALVING Simple curved edge half‐lap joint. The parts are identical. This joint is decorative compared to a normal half‐lap but is also stable. The curves provide some extra tensile strength as well as increased glue area along the sides of the joint. In all half lap joints the material thickness is critical to a accurate fit. T o
CNC FRAME JOINTS DOVETAILED CROSS HALVING This joint has two identical parts. They provide a high degree of racking resistance and lot of glue area. T o
CNC FRAME JOINTS CROSS MITER JOINT WITH JIGSAW KEY This joint allows four separate members to join at a common intersection point using a jigsaw key. In a tight fitting joint this is very difficult to take apart so it can't be considered knock‐down.In a joint loose enough where the joint can be easily taken apart the holding of the four members are not very rigid. T o
CNC FRAME JOINTS STOP LAP WITH JIGSAW KEY The jigsaw key provides some tension resistance. This joint also has a notch cut in the edge so the cross member can resists lateral stresses as well. T o
CNC FRAME JOINTS JIGSAW MITER JOINT Another decorative half‐lap corner joint that provides resistance to pulling apart due to the interlocking parts.. T o
CNC FRAME JOINTS DOVE TAIL KEY CORNER This joint has a separate key to resist the tensile stresses on the joint. Note that the parts do not have to be at a right‐angle T o
CNC FRAME JOINTS SHOULDERED DOVETAIL HALVING Another half‐lap variation with a dovetail. This joint has a notch cut in the edge so the cross member is less likely to shift laterally. Thus the joint resists forces in all directions. T o
CNC FRAME JOINTS HOOKED JIGSAW HALVING These last two joints have one member extending beyond the edge of the other. In this case the hook extends fully through the piece providing some tensile resistance. T o
CNC FRAME JOINTS DOUBLE JIGSAW-HOOK CORNER This is a decorative corner joint which provides resistance to tensile stresses. The extension could be used as a hook: T o MORE INFORMATION ABOUT JOINERY THE ART OF JAPANESE JOINERY (KIYOSI SEIKE) –BOOK JOINT BOOK : THE COMPLETE GUIDE TO WOOD JOINERY WOODWORKER´S GUIDE TO JOINERY 50 DIGITAL JOINS
Tear out on the edge of pieces is more problematic with router bits. This needs to be carefully setup so the tool approaches the work properly. Router bits also exert more force on the workpiece while cutting necessitating stronger fixturing. – When routing plywood contour cuts are usually machined with a compression bit. This bit pushed down from the top and lifts up from the bottom to reduce tearout in sheet goods. Pockets are usually cut with down shear bits to reduce tearout. • Corners: Square corners can’t be cut with cylindrical router bits. For many cases this means joints need to be designed with rounded corners. The rounded corners can be drilled out or routed. A key with routing these corners is that the tool must keep moving while making the cut. Otherwise excessive heat develops. This leads to greatly increased tool wear and the potential for fires. – See CNC Corner Fix Utility for a program to help in quickly drawing these rounded corners in Rhino. There are some issues associated with CNC cut joints which need to be understood. CONSIDERATIONS CNC WOOD JOINERY
are cut to the same dimension they obviously won't fit together. A gap needs to exist between the parts for them to slide by one another and provide a small space for glue. In CNC work it's common to use a gap of 0.005" per side of the joint. So for example a tenon should be cut 2 times 1,2mm narrower than the mortise (1.2mm on each side). This is a fairly tight fit but will work if the machine is very accurate and the tools are sharp. If the tools are dull, the cut is not as clean and the accuracy can't be maintained. Therefore it is sometimes necessary to use 0,25mm per side. Most of the joints shown below were cut with 0,25mm per side. This was done to allow the pieces to slide apart easily for demonstration purposes. • Stock: Material thickness variations have a big impact on CNC cut joints. The toolpath programming will be done for a certain thickness. If the stock is not that thickness exactly it will affect the fit of the joint. For this reason using "Stock to leave" and "Floor to leave" parameters in the CAM software can provide offsets to compensate for the variation. • Fixturing: Rather than moving the work piece over the tool, the work must be held securely while the tool moves. The process of securing the work is called fixturing. In the case of 3-axis routing of plywood this usually just means tabbing the parts. In hardwood this often involves double-sided tape holding the parts to a spoilboard.
see a deviation in thickness in some of the joints it is usually this material thickness difference which is the cause THAT IS WHY IS SO IMPORTANT TO MEASURE PRECISELY YOUR MATERIAL ! USUALLY THERE IS A DEVIATION OF 0,1-0,3MM
which a cutting tool follows to machine a part. They are represented on the screen by lines and curves which represent the path of the bottom center of the cutting tool. Pocket toolpaths etch the surface of the material, while profile toolpaths cut all the way through.
the language that the machines talk, they can understand standart one of speak another “ dialect” depends on the firmware of the machine. Is just a series of numbers with letters, like directions on maps or a gps so the machine know what it has to do and with actions has to take. IMPORTANT CODES. • X / Y / Z ABSOLUTE POSITIONING • M02 / M30 END OF PROGRAM • G 20 PROGRAMING IN INCHES • G 21 PROGRAMING IN MM • G 00 RAPID POSITIONING • G01 LINEAR MOVEMENT (CUTTING)
, 0 , 0 IMPORTANT WORDS • ROUGHENING REMOVING MOST MATERIAL BUT NOT ALL • FINISHING FEMOVING MATERIAL UP TO DESIRED SHAPE • PROFILE CUTTING AROUND A LINE • STEP OVER HOW MUCH OF THE CUTTER IS CUTTING • STEP DOWN CUTTING DEPTH IN ONE PASS • FEED CUTTING SPEED • PLUNGE CUTTING STRAIGHT DOWN • LEAD IN/ENGAGE HOW TO MOVE INTO CONTACT • POCKETING CUTTING INSIDE OF SHAPE • FACING CUTTING ALL • STOCK THE PIECE YOU WANT TO CUT
THE PROGRAM • DXF ALWAYS A GOOD START, OLDER VERSIONS ALWAYS BETTER • STL BINARY TYPE ALSO IS USUALLY COMPATIBLE • PNG FOR 2D-3D WITH OUTLINES OR GRADIENTS • SVG FOR 2D FILES TROUBLESHOOTING • TRY WITH ONLY ONE SOLID NOT MULTIPLE SOLIDS • MESH OFTEN DIFFICULT TRY SOLID OR CURVES • ONLY SOLIDS? TRY TO CHANGE TO CURVES • ADD EXTRA CURVES ON CAD MODEL
SHOPBOT TURN UP THE MAIN POWER SWITCH AND IN CASE YOU HAVE TURN THE SECURITY KEY LOCATE THE POWER SWITCH (CONTROL BOX) AND THE 2 EMERGENCY STOP BUTTONS
thumb screw to drop the dust shroud for better access to the spindle Unscrew using the provided wrenches so you don´t damage the collet. Clean properly the collet and collet nut from dust. Assemble again with your bit and tight everything. Don´t forget to secure your material properly.
SOFTWARE • BUNDLED WITH MANY CNC MACHINES • TIMING SENSITIVE • KEEP PC CLEAN! • LAPTOP NOT GOOD (POWER SAVING,ETC) • NEED PARALLE PORT • SUPPORT 2.5D MACHINING FROM BMP/JPEG
OF BITS AND MATERIALS Frequency on VFD Rounds per minute Material x 3000 Aluminium 150 x Model Wax 200 10000 Plastics 270 13500 Most plywood, MDF, and so on. 300 15000 Hardwood DIFFERENTS REQUIREMENTS DEPENDING ON THE PROGRAM WARM UP THE SPINDLE, ONLY IF THE MACHINE HASN´T BEEN USED RECENTLY AND THE BEARING ARE COLD
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![CNC WORKSHOP by EDUARDO CHAMORRO MARTIN [email protected]](https://files.speakerdeck.com/presentations/b3bb9c274bba4f5aab42255665d552de/slide_0.jpg){kind=link}
