Adding Spindle Direction And Coolant Control To Your CNC Machine

June 20, 2014 by Rich Bremer 11 Comments

CNC3020 spindle direction control and coolant system

[Peter] is back at it, again modding his CNC3020 router. This time he’s adding a coolant system and spindle direction control. If you have ever tried cutting plexiglass using a mill, router or even a band saw, then you know it is common for those plastic chips to melt together and form a crusty trail of goobers directly behind the cutting tool. Turning down the spindle speed helps a little but the intent of the coolant system is to eliminate the globular mess all together.

It appears the coolant flow is open loop, meaning the initial coolant reservoir is not replenished automatically. The coolant starts in a container and is moved via a pump through a silicone hose. At the end of the hose there is a nozzle mounted to the Z axis which points the coolant stream at the tool bit. The nozzle is plastic and made from a re-purposed and modified flux application container. [Peter] took advantage of the machine’s bed being made of slotted extruded aluminum. The bed catches the coolant which then travels down the channels to the front of the machine where it is collected in a custom made bin. The parts of this plexi bin were actually cut out using this machine! Gravity then drains the contents of this bin into another container residing at a lower altitude.

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Laser Cut Miter Joints

June 15, 2014 by Brian Benchoff 14 Comments

polyhedra Every project deserves its own laser cut enclosure, of course, but the most common method of joinery – an overabundance of mortises and tenons, and if you’re lucky, a bit of kerf bending – is a little unsightly. Until tastes in industrial design change to accommodate this simple but primitive method of joining two laser cut panels together at an angle takes hold, the search will continue for a better way to cut acrylic and plywood on a laser cutter. The folks at Just Add Sharks might have a solution to this problem, though: miter joints with a laser cutter.

Instead of the slots and tabs of the usual method of constructing laser cut enclosures, miter joints produce a nearly seamless method of joining two perpendicular panels. The key, of course, is cutting a 45° bevel at the joint and gluing or fastening the pieces together. Just Add Sharks is doing this with a laser cut jig that holds a plywood or acrylic piece at a 45° angle to the laser beam. Yes, it’s only one cut per pass, but after adjusting the depth of cut to 1.4 times the thickness of the material, miter joints are easy.

Using a laser for miter joints isn’t limited to 45°, either. There are a few examples of an octahedron and icosahedron. Of course fastening these mitered panels together will be a challenge, but that’s what clamps and glue are for.

Better Lasing With Pulses

June 11, 2014 by Brian Benchoff 24 Comments

laser

The folks at the Lansing, Michigan hackerspace built themselves a 40 Watt laser cutter. It’s an awesome machine capable of cutting plywood and acrylic, and is even powered by a RAMPS board, something normally found in 3D printers. They wanted a little more power out of their 40 Watt tube, though, and found pulsing the laser was the best way to do that.

Unlike the fancy Epilog and Full Spectrum Laser machines, the Buildlog.net 2.x laser cutter found in the Lansing Hackerspace didn’t use Pulse-Per-Inch (PPI) control until very recently. When a laser tube is turned on, the output power of the laser is much higher – nearly double the set value – for a few milliseconds. By pulsing the laser in 2-3 ms bursts, it’s possible to have a higher effective output from a laser, and has the nice added benefit of keeping the laser cooler. The only problem, then, is figuring out how to pulse the laser as a function of the distance traveled.

To do this, the laser cutter must accurately know the position of the laser head at all times. This could be done with encoders, which would require a new solution for each controller board. Since laser cutters are usually driven by stepper motors controlled with step and direction signals, a much better solution would be to count these signals coming from the CNC computer before it goes to the RAMPS driver, and turn the laser on and off as it moves around the bed.

A few tests were done using various PPI settings, each one inch long, shown in the pic above. At 200 PPI, the laser creates a continuous line, and at higher PPI settings, the lines are smoother, but get progressively wider. The difference between PPI settings and having the laser constantly on is subtle, but it’s there; it’s not quite the difference between an axe and a scalpel, but it is a bit like the difference between a scalpel and a steak knife.

It’s an impressive build for sure, and something that brings what is essentially a homebrew laser cutter a lot closer to the quality of cutters costing thousands of dollars. Awesome work.

Not Having The Room Isn’t A Good Reason To Not Have A CNC Router Anymore

June 7, 2014 by Rich Bremer 35 Comments

PhlatPrinter CNC Machine

Typically, CNC Machines take up a larger footprint than that of the raw material it is cutting. The size of such a machine may have prevented interested makers/hackers from buying or building one for themselves. If you are one of those people then you’d be interested in [Fly3DMon’s] series of CNC Router projects called PhlatPrinter.

A typical CNC Router has a bed that the work piece is mounted to and that work piece stays stationary. The tool then moves in 3 axes, removing material, leaving behind a finished part. The PhlatPrinter works more like a large format plotter, where the work piece is moved back and forth via rollers while the tool only moves in 2 directions. What this allows is a CNC Machine that takes up very little floor space when not in use that can handle any length of material!

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Lathe CNC Upgrade Is Nothing To Shake A Turned Stick At

June 6, 2014 by Rich Bremer 30 Comments

7x12 CNC Lathe Conversion

We see a lot of CNC Machines here on Hackaday but not too many of them are lathe-based. [Jim] sent us an email letting us know his dissatisfaction regarding the lack of CNC Lathes and included a link to one of his recent projects, converting a small manual lathe to computer control. This isn’t some ‘slap on some steppers‘ type of project, it’s a full-fledged build capable of tight tolerances and threading.

The project is based on a 7×12 Mini Lathe. There are several brands to choose from and they are almost identical. Check out this comparison. [Jim] started with Homier brand.

The first thing to get upgraded was not related to the CNC conversion. The 3″ chuck was replaced with a 5″. Changing it over was easy using an adapter plate made for the task. For the X Axis, the stock ways and lead screw were removed and replaced by a THK linear slide. This slide only has 2.5″ of travel and is perfect for this application. The travel being so short allowed the final eBay auction price to be under $40.

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DIY Newton’s Cradle Uses Parts Designed On A Smart Phone

June 6, 2014 by Rick Osgood 13 Comments

Injection Molded Parts

As far as physics demonstrations go, the Newton’s Cradle is probably one of the most recognizable. Named after Sir Isaac Newton, the Newton’s Cradle demonstrates the law of conservation of momentum using swinging ball bearings.

[Scorchworks] decided he wanted to build his own Newton’s Cradle. The frame appears to be cut from MDF or particle board and then screwed together. That material is really easy to obtain and also to work with using inexpensive tools. The tricky part was the ball bearings. Most of the time when you see a Newton’s Cradle, the ball bearings have a small hole drilled in the top with an eye hook attached. The string is then attached to the eye hook.

[Scorchworks] decided to do something different. His plan was to make custom injection molded plastic rings that would fit perfectly around the ball bearings. The most interesting thing is that he designed the injection molding plates entirely on his smart phone while at his child’s baseball practice. To do this, [Scorchworks] used his own Android app, ScorchCAD. ScorchCAD is a free clone of OpenSCAD that is designed to run on Android devices. Most of the functionality of OpenSCAD has been implemented in ScorchCAD, though not all functions work yet. You can find a list of all the supported functions on the project’s website or in the Google Play store.

Once the plates were designed within ScorchCAD, [Scorchworks] exported the STL file and then used Meshcam to generate the gcode for his CNC milling machine. Once he had the plates machined, he just placed the ball bearing into the mold and injected the molten plastic around it. The plastic formed a perfectly shaped ring around the bearing with small loops for the string. [Scorchworks] repeated the process several times to get all of the ball bearings finished.

Finally, the bearings were strung up using some fishing line. A Newton’s Cradle is very sensitive to the positioning of the ball bearings. To account for this, [Scorchworks] tied each end of the fishing line to two different screws on top of the cradle. This way, each screw can be tightened or loosened to adjust the position of each ball bearing.

Building A CNC Milling Machine For Less Than $1300

June 1, 2014 by Mathieu Stephan 34 Comments

[Mynasru] tipped us about a homemade CNC milling machine that his friend [trochilidesign] recently made. We have to admit it may be one of the best ones we’ve featured so far on Hackaday, mainly due to its elegant design (see picture above) and its all metal structure with linear guide rails. In the very well detailed write-up, we can gather that the CNC machine was designed using SolidWorks.

The main frame is built around 2 Maytec 40x80mm profiles and 2 endplates made from 10mm thick aluminum. 3 Nema 23 stepper motors and their drivers power the build, all of them bought on ebay. Finally, the Mach3 CNC software was chosen to interpret the G code and send the appropriate control signals.

Due to licensing restrictions the original author can only provide us with PDF files detailing each part of the machine, but we’re sure this should already be enough for interested persons out there.