PCB Toner Transfer Method, Now Without The Transfer

PCB Laser Printer

A common way to create a custom PCB at home is to do what is called the Toner Transfer Method. In this process, the trace layout of the board is printed out on a piece of special toner transfer paper that allows the ink to come off in the following step. The toner transfer paper is then put print-side-down on a copper clad PCB blank, heated and pressed with an iron. The heat and pressure from the iron transfers the toner from the paper to the copper. The exposed copper then is chemically removed, the previously applied toner protects the copper in the pad and trace areas. The toner is then removed using paint thinner.

That is a long process with many critical steps. [mlerman] wondered why no one was printing the toner directly to the PCB. He has been tinkering with printing directly on PCB blanks for 4 years now. He’s made hundreds of boards over that time and can now make a PCB in under 15 minutes.

The obvious route to take would be to modify a current laser printer to accept the much-thicker-than-paper PCB boards. A few printer models were tried but [mlerman] feels the Lexmark E260 works the best due to the cost, internal mechanical components and an easily modifiable manual feed system. There is also a Local Printer Utility that allows the majority of the printer parameters to be adjusted.

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Bench Top Drill Press Converted To Milling Machine, Mounted To Lathe

Convert a Drill Press to a Mill

Milling machines are nice to have around for precisely drilling holes or removing unwanted material from a part. However, they can be expensive and may not get a lot of use, two reasons why a mill purchase may not make sense for a home shop. [David] didn’t need a mill, he wanted one and he didn’t want to spend a lot of money. He did have an old bench top drill press and a lathe in his shop and thought it would be a good idea to combine them them into a DIY Milling Machine.

The problem with just throwing a milling bit in a drill press and trying to mill metal is that the drill press spindle ball bearings are not made for radial loading. [David] knew this and replaced the stock ball bearings with angular roller bearings. These new bearings would require an axial preload applied to keep the spindle in place. This was done by machining threads into the spindle’s shaft and adding a nut to secure and preload the new angular roller bearings.

[David] did not have an XY Table to donate to the project so he decided to mount the drill press to his lathe and use the lathe axes to move the work piece around underneath the mill. Thick plate steel was welded together to form a hefty bracket that bolted to both the lathe bed and drill press column. And yes, the lathe is still functional and the changeover process is simple. To go from Mill to Lathe; the work piece is removed from the lathe’s cross slide and replaced with the lathe tool holder. That’s it!

Overall, [David] is happy with his conversion. He doesn’t expect his project to be as precise or rigid as a proper milling machine but says he has no problem cutting 1mm deep passes in steel when using a 6mm diameter mill bit.

PrintBot Prints On The Ground, Uses Talcum Powder

PrintBot prints talcum powder on your floor
Yes, this is a printing ‘bot but it’s not a 3D Printer. Even though it’s called Printbot, don’t get it confused with other products that may begin with ‘Print’ and end in ‘bot’. Printbot is half Roomba, half old inkjet print carriage drive and the remaining half is a small PC running Windows CE.

The whole point of this ‘bot is to draw/write/print things on the floor. No, not in ink, in talcum powder! The Roomba drives in one axis as the powder is systematically dropped in the ‘bots wake. It works one line at a time, similar to how a progressive scan TV displays an image on the screen. The PC on board the Printbot reads 8-bit gray scale images from a USB drive, re-samples the image and outputs the image one line at a time to an external microcontroller. The microcontroller is responsible for driving the Roomba forward as well as moving the hopper’s position and dispensing the powder in the correct place. Check out the small photo below. That black and white strip is not there for good looks. It is part of the encoder positioning system that is responsible for communicating the location of the hopper back to the microcontroller.

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CNC Router Converted To 3D Printer

CNC Router Converted to 3D Printer

3D Printers have come down significantly in price over the past few years. Nowadays it is even possible to get a 3D printer kit for between $200-300. It’s arguable how well these inexpensive printers perform. [Jon] wanted a printer capable of quality prints without breaking the bank. After researching the different RepRap types that are available he concluded he really wasn’t up for a full machine build. He had previously built a CNC Router and decided it was best to add a hot end and extruder to the already built 3 axis frame.

The CNC Router frame is made from aluminum, is very rigid and has a 2′ by 2′ cutting area. All axes glide smoothly on THK linear bearings and are powered by NEMA 23 motors driven by Gecko 540 stepper drivers. The router was removed from the machine but the mounting bracket was left on. The bracket was then modified to hold the extruder and hot end. With 3D Printers there is typically a control board specifically designed for the task with dedicated outputs to control the temperature of the hot end. Since [Jon] already had the electronics set up for the router, he didn’t need a specialized 3D Printer control board. What he does need is a way to control the temperature of the hot end and he did that by using a stand-alone PID. The PID is set manually and provides no feedback to the computer or control board.

Huge Whistle[Jon] used liked Mach3 for controlling his CNC Router so he stuck with it for printing. He’s tried a few slicers but it seems Slic3r works the best for his setup. Once the g-code is generated it is run though Mach3 to control the machine. [Jon] admits that he has a way to go with tweaking the settings and that the print speed is slower than most print-only machines due to the mass of the frame’s gantry and carriage. Even so, his huge whistle print looks pretty darn good. Check it out in the video after the break…

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4 Axis CNC Foam Cutter Sports A Unistrut Frame

DIY foam cutter made from Uni-Strut.

CNC Foam Cutters are capable of cutting out some pretty cool shapes that would otherwise be extremely difficult to do. They do this by pulling a heated metal wire though a block of foam. Electrical current passing through the wire heats it up causing the foam to melt away, there is no dust and no mess to clean up. [batchelc] decided to make his own large-scale CNC Foam Cutter and took a lot of photos along the way.

Since machine is 4 axis, meaning both sides can move forward/back and up/down independently of each other, tapered shapes are possible. One example where this would be helpful is cutting wings that are swept or have different profiles at each end.

DIY foam cutter made from Uni-Strut.

The main frame of the machine is made from Unistrut and measures a whopping 60 by 60 inches. Subtract the size of the mechanical components and the cutting area ends up being 48 by 42 and 22 inches high. The foam sits on an MDF bed, gravity is the only method of holding the foam down during cutting. The wire doesn’t actually touch the foam so there is no force applied to cause it to move. The hot wire moves slowly and melts the foam just a few thousands of an inch in front of the wire resulting in no contact between the two.

Both axes on each side are driven by 1/2-10″ lead screws supported by bearing blocks on both sides. The longitudinal axes smoothly traverse the length of the machine by means of skate bearings that ride on the Unistrut channel itself. The vertical axes have a plastic bushing that slides along a round shaft.

The control portion of the machine is a HobbyCC FoamPro kit that came with the 4 axis stepper motor control board and 4 NEMA 23 stepper motors. GMFC software is used to both generate the g-code and send the commands to the stepper motor control board.

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Your Living Room Becomes Next Mario Kart Course

RomoCart, Indoor Robot Racing

[Ken] likes his living room and he is on a continual mission to make it more interesting. Recently, he has made a giant leap forward with a racing game project he calls RomoCart. Think of it as a partially-physical game of Mario Kart. You are able to race others around a track while still having the ability to fire projectiles or drop defensive measures in efforts to win the race!

First, lets talk about the hardware required. The racers are standard Romo educational robots. Wireless game controllers provide the means for the drivers to control the Romos. Hanging from the ceiling is an Xtion motion sensing camera and a video projector, both pointed down at the floor.

To get started, the system scans the floor and determines a race course based on the room layout and any physical objects in the vicinity. A course is then generated to avoid the obstacles and is projected onto the floor. At this point it would still be a pretty neat project but [Ken] went way further. The ceiling-mounted camera tracks the motion of the Romos driving around the track and the video projector displays a smoke trail behind each racer. Randomly displayed on the track are items to help you win the race, including an acceleration item that makes your Romo go twice as fast for a short time.

Have a tailgater? No problem, just pick up some bananas and drop them on the track. If a following competitor drives into one, they spin out. If you want to get super rude, pick up some missiles and fire them at the racers ahead of you. A direct hit will stop them right in their tracks.

[Ken] is no stranger to HaD, he’s had a few of his projects covered here before. Check out his Tempescope, Moving Window and his Autonomous Lighting System.

Check out a video of the racing in action after the break. It is amazing!

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DIY Camera Stabilizer Takes The Shakes Out Of Filming

 

DIY Camera Stabilizer
We’ve all prematurely stopped watching some Youtube video because of shaky camera work that makes the video unwatchable. There is a solution available for this problem, it’s a device called a camera stabilizer and it is designed to compensate for jerky camera movement. There are several types available for purchase but they can get fairly expensive. Even the cheaper ones at a few hundred dollars are not economical for hobbyists. [John] set out to make his own camera stabilizer using some unorthodox parts.

[John's] chose a gimble style design that effectively lowers the camera’s center of gravity down close to the camera persons hand. The handle of the device must also be mounted in a manor to prevent angular and rotation movement of the supporting hand from transferring to the camera.

The handle is from a cement trowel, on top of which is a ball bearing mounted to a threaded rod. A PVC fitting was heated to soften it and the bushing pressed in. This bearing is responsible for allowing the rotational freedom between the handle and the camera. To decouple any angular movements, two hinges were attached to the PVC fitting. The hinges are perpendicular to each other, one allows forward-back tilting while the other allows left-right tilting. The upper hinge is attached to a piece of poplar wood that also serves as a base for the camera.

At this point, if you were to try to hold this contraption with the camera installed, it would immediately tip over due to gravity. To prevent this, the center of gravity of the moving parts (including the camera) must be lowered. [John] did this by using some aluminum tubing to support wood weights that reside lower than the pivot points created by the hinges.

If you like the DIYer-style stabilizers, check this other wooded one out. Want something more polished looking? How about this pistol grip stabilizer?

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