Aug 11 2016

CNC machine Attachments

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When you first buy (or build) a CNC machine your primary concern when working on your budget is likely going to be figuring out what the best quality parts you can afford are. Every machinist, from professionals to hobbyists, wants to get the best CNC machine that they can in order to make machining processes as smooth as possible. While you should certainly concern yourself with the necessary parts of the machine first, so that it can actually run, there are additional considerations you can take. Attachments (or accessories, add-ons, or whatever you wish to call them) may not technically be essential to the running of a CNC machine but once you start using them they can be so beneficial that they will certainly start to feel like necessary components.
Some attachments are so common that many machinists would likely argue that they are essential components to any CNC machine. Ruin boards are a great example of an attachment that fit into this category. Image that you have your CNC machine set up and you are ready to machine your first project on your nice, new t-slot table. With what you just paid for that t-slot table you can picture what a nightmare it would be to accidently cut right into the table and destroy it. Keeping a ruin board between the table and your material should stop this from ever happening. Ruin boards do not need to be too thick; usually something between ⅛” and ¼” will work fine. New machinists may want to use a thicker board to leave more room for error.

CNC machine clamps

CNC machine clamps

Clamps are another great, yet simple, attachment that most basic CNC machines should include. Any level of precision machining will require you to hold your material still. There are a lot of ways to do this and clamps are one of the easier and more cost efficient methods. Sometimes you may have other methods available; t-slot tables utilize t-slot nuts, step blocks, step clamps and other implementations but it can be a hassle to find pieces that fit the specific table you are using. Making a clamping system of your own can be much more effective. Be creative and try to develop an easy-to-use system that works well with your equipment and set-up.
In some cases clamps may not be a good hold-down method because the item you are machining is too small. When you find that your clamps are too large, a milling vice is an excellent alternative tool. While a regular vice could be jury rigged to your table, a milling vice is designed specifically to work with a CNC machine table and they tend to be extremely precise. There are many different types and brands of milling vices in many different sizes so determine your needs and do a bit of research before committing to anything expensive.
Once you have a hold-down system in place you can start actually machining. On any project you want to make sure that everything has been machined accurately and there is no set of tools better for this than a pair of calipers. Digital calipers are the way to go for their extreme precision; 0” – 6” calipers will work fine for the vast majority of measurements you need to take while examining the finer details of projects. Cheaper calipers work fine but like any other tool you will want to go for the higher end of tool quality and price range as your budget allows.

 air sprayer for cnc machine

air sprayer for cnc machine

During and after machining, chip evacuation will be one of your primary concerns. Using an air sprayer is the best way to clear out chips while your CNC machine is running. Any standard air compressor with a trigger nozzle can do this well. Clearing away chips during the cutting process is often a critical procedure. After your machining has been completed you will want to use a shop vac’s powerful suction to get all of the chips out of your work area, leaving everything crisp and clean for your next project. Any time you are working with chips, and when using a CNC machine in general, always remember to wear safety goggles.


Jul 21 2016

CNC machine for making music

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Since long before recorded history began, people have made music. From something as simple as banging rocks together to an endeavor as complex as performing an opera, people have always had a fascination with music as a medium of storytelling and a form of entertainment and we likely always will. In modern times people who think of music generally think of instruments. Having access to a CNC machine allows anyone to make a musical instrument of their very own for all musical entertainment purposes. But music is not limited to traditional instruments alone. Anyone who has seen the theatre performance Stomp or similar shows knows that even everyday objects can be used to make music. While a CNC machine is not an everyday object they too can be used to make music, in a more literal sense than machining an instrument.

Making guitar with cnc machine

Making guitar with cnc machine

Most instruments are made from either metal or wood, which just so happen to be two of the most common materials used by hobbyists for their at-home CNC machining projects. One of the most popular instruments that hobbyists seem to go with is the guitar. There are dozens of different types of guitar designs that you can choose from. Many guides exist on the Internet for making a guitar with a CNC machine. While the general process is primarily the same for most guitars it will be the customization process that is the heart of this project. You may be able to find files and just make the guitar straight away from those but you also have customization options. This guitar can look however you want it to look like. Maybe there is a guitar you like but that you wish was a bit different, allowing you to use that guitar as a blueprint and tweak the design to fit your own tastes. Or maybe you want to be really creative and design something completely from scratch to fit your own mental image of the perfect guitar. This same principle applies to most instruments, depending on their level of popularity. You are more likely to find help and support videos for more commonplace instruments, like a violin, than for rarer or larger items like a cello. Those of you who work with metal can also pursue this project by making saxophones, trumpets or other instruments constructed from metals. Regardless of what type of materials you are using you do not have to create an entire instrument either. If you already have a ready instrument you could make new individual parts to replace, repair or upgrade various components of those items.

CNC machine for making guitar

CNC machine for making guitar

Besides producing instruments to make music, CNC machines can be used to make music themselves. The key to this process is to figure out a combination of feed rate and distance along an axis that will allow the stepper motor to spin at a frequency that mimics a musical note. With a bit of tinkering you can produce chords to replicate songs or to even entirely new tunes of your own. A more in-depth explanation of this process, as well as several musical examples based on popular video game soundtracks, can be found at http://tim.cexx.org/?p=633. Another example (https://www.youtube.com/watch?v=jAWF-qhh4pQ) shows a synchronous motor that has been set up to play the song “The Imperial March” from the film “Star Wars Episode V: The Empire Strikes Back”. In the first example MIDI (mid2cnc) script is use to generate these musical results. While the sounds you generate may not be as spot on as an orchestra directed by John Williams it can be very fun to get an additional use out of your machine while getting to do something a bit different with it.


Jul 7 2016

Climb and conventional milling secrets that you should know

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When a cutter moves through material it can mill up (conventional milling) or down (climb milling). Many machinists use climb milling for most, if not all, of their CNC projects. Climb milling is known for producing better surface finish than conventional milling and overall does have more advantages than conventional. However, climb is not always the better of the two options and any machinist should know that there are times when conventional is preferable, and when those times are.

Climb and Conventional Milling

Climb and Conventional Milling

Using climb milling, each tooth on your cutting tool makes contact with the material you are working with at a defined point and moves out, cutting thinner parts of the material until it is no longer touching the material. So, the width of the material being cut starts at the maximum length and decreases to zero as the cutter moves. This causes chips to be thrown behind the cutter, making chip removal an easier process while machining. Tool life is also extended because each tooth on the cutter is not rubbing against the material. One of the major downsides of climb milling is that it can potentially produce a lot of backlash. As a result this method should mainly be used on machines that can eliminate large amounts of backlash and it may not always be usable with older CNC machines.
Conventional cuts in the opposite direction of climb. Using conventional milling, the teeth of the cutter will start at zero thickness and work their way up to the maximum thickness that you are cutting. When first making contact with the material your cutter does not even cut the material; it slides across the material surface until enough pressure is built up for the tooth to dig in and begin cutting. This causes the work material to become hard and somewhat deformed and also causes cutters to dull faster than when using climb. The sliding and biting of this cutting process also tends to leave an inadequate surface finish on work materials. On the upside this process does not generate anywhere near as much backlash as climb and is a perfectly sound cutting method on almost any CNC machine. The two methods do not have to be used independently either; climb can be used for rough passes while conventional milling is used for finishing passes.
Climb does have a few distinct advantages over conventional when your machine can manage it. As mentioned before, your tool life will be longer, surface finish will be better and chip removal is much easier. Additionally, you do not need as advanced of a hold-down system. Climb exerts force downwards instead of upwards like conventional milling. You can also use higher rake angles while climb milling, saving you a little money on the amount of power needed. Just do not forget about the excessive backlash when looking at all of the positives of climb milling.
When using climb milling, deflection can causes some problems with surface finish. Climb cutting causes tools to deflect, deforming the surface finish of projects and leaving you with less than adequate results. If you run into this issue try switching to conventional cutting; that will likely make a big enough difference to correct any issues you are having with maintaining a good surface finish. While conventional cutting can help it will not always fix your problems. If you have tried climb cutting and conventional cutting and are still having issues you can decrease deflection further by reducing the depth of your cuts. Using a small amount of your cutters diameter will make it less likely that you will experience any deflection.


Jun 23 2016

Easter egg design with Eggbot & CNC Egg Decorating

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Easter egg design with Eggbot & CNC Egg Decorating

Decorating eggs is an age old past time for children, especially in the spring when it starts getting close to Easter(easter egg design). Traditionally, you would take an egg and color it by hand. But like many older past times, this task has been made faster, better and more efficient through the innovation of modern technology. This particular CNC machine may have a very specific function but it is a basic machine that serves as a good way to teach CNC technologies to children and young adults. The name of this machine is the EggBot.

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Jun 9 2016

Acrylic Glass Routing (Plexiglas)

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Acrylic Glass Routing (Plexiglas)

Routing acrylic materials (Plexiglas, Lucite, Acrylite, Perspex, etc.) is one of the most popular methods used in the fabrication of this type of material. A high quality standard kept for the material regardless of how it will be used is routing the product with a fine finished edge, eliminating the need for finishing the item after it has been routed. There are a number of key factors you will need to take into consideration to keep your finish high-quality, two of the most important factors being tooling and programming.

CNC acrylic

CNC acrylic

There is a lot that could be said about tooling if we were to get into specifics but there are some more basic guidelines you can follow for acrylic routing. When you are choosing which tool to use the first criteria that affects your choice should be diameter. On a lot of jobs clients commonly have requests that will require you to use tools that are 1/8” to 1/4″ in size. Using larger tools, from sizes of 3/8” to about 1/2″, will result in consistent surface finish results that are superior to smaller tools. The increased stability and flute depth of tools with larger diameters cause the increase in quality. Any tool that is larger than 1/2″ will only improve your results slightly and as you use larger and larger tools the size increase will eventually do more harm than good. Using anything bigger than 1/2” is unnecessary. Additionally, your cut depths should not exceed 2”. Once you have selected your diameter the next thing to choose is cutter configuration. Generally speaking, the smaller the diameter of your cutter the more likely it is that a spiral configuration will leave a good finish. When you use larger tools (3/8” and up) a straight flute works better. If you are using a tool that is 1/4″ or smaller a single edge spiral O-flute will give the best finish. At larger sizes low helix multi-fluted tools work better (the exact type of tool you will need depends on if the acrylic is cast or extruded and on any fillers that may have been used in the material’s manufacturing). These are the sizes where you will want to use double edge straight tools. O-flutes and V-flutes can both work well when using tools of these sizes. In addition to these conventional tools there are also some specialty tools on the market for this kind of work so it does not hurt to do a little research and see what is available.
When you are programming it is key to select the correct cutting methods and cutting parameters. Every different combination of material and cutter will have its own “sweet spot” that you want to hit for ideal machining. Your feeds and speeds are going to be the most sensitive parameter while you are programming. Acrylics (and other plastics) have a very small chip load range that you need to find in order to maintain a sufficient finish. Each cutter is going to have its own optimum chip load for every different type of material. You need to look up the feeds and speeds that you will need or, if that is not possible, experiment until you find the right configuration. Once feeds and speeds are settled you will select your cutting method. Conventional and climb cutting are both good but tools with larger diameters work better with conventional cutting. With smaller diameters the cutting method you need will depend on the material; you will have to do some trial-and-error work to figure out what works best. If you are new to working with the type of acrylic you are using some trial-and-error experimentation will be necessary to figure out a lot of parameters like finish passes, depths of cut and entry points. There is a lot to learn about this type of work but with time and practice you will get the hang of it and be machining like a pro in no time.