How To Make a Brushless Motor for Education

Exploring electromagnetism with DIY laser cut motor

laser cut brushless motor

Teaching kids about how motors work can be a lot of fun, particularly when they get to build and experiment on the motors themselves. So when engineer Matt Venn spotted a neat little 3D printed motor, he decided to make his own variation – this time using laser cut components and an Arduino to run the show.

The learning experience

Once all the kinks were worked out, the Arduino was replaced by a few cheap electronic components. This way, students have the opportunity to build the entire setup from scratch, mounting the electronics on a breadboard as they work out exactly what each component does.

The adjustable laser cut rotor has slots to hold different numbers and configurations of magnets, and this can be further extended by cutting custom rotors to suit alternate magnet arrangements.

This is a great project that encourages a hands-on approach to exploring electromagnetism by building a simple DC brushless motor. Consideration has been made to come up with a laser cut solution that can be assembled and studied within the time constraints of a science class workshop.

Matt has provided all of the files and extra info you need to get the motor up and running on GitHub, where you will also find a brief video walkthrough that highlights how the motor and supporting circuitry work.

Matt Venn via Hackaday

How To Make a Laser Cut Dremel Chop Saw

Industrialize your mini DIY production line

dremel chop saw 1

Repetitive cutting for projects that require precision parts can be a time-consuming process. The need for consistency and accuracy in making several hundred cuts from small diameter pipes prompted sculptor HTMF Metal Pizza to seriously upgrade his DIY production line.

Why not use a pipe cutter?

The usual way to cut sections from the hobby pipe is to use a pipe cutter, however this tool leaves a small deformation around the inner diameter. Normally this wouldn’t be an issue, but as HTMF’s process requires smooth edges on both inner and outer surfaces, the sections from the pipe cutter are unsuitable for his needs.

Solution: the Dremel abrasive disc

An abrasive disc spinning at high speed will cut with the precision that HTMF is looking for. When controlled in smooth linear movements, the cuts will be quick and clean… so armed with this knowledge he set out to optimise the cutting process to achieve greater speed without sacrificing any accuracy.

“While I tried cutting the tubing free hand, I found I needed a third hand and there was a huge variation in size which required a great deal of re-finishing.”

Introducing the laser cut Chop Saw

The solution was to build a miniaturised ‘chop saw’ mount for his Dremel cutting tool. As well as holding the Dremel and working material securely, the chop saw houses two drawers; one to store Dremel parts and another to catch the pipe sections as they are cut. He also added a scale on the cutting table that aids in achieving consistent lengths with each cut.

dremel chop saw 2

See the full tutorial on how to build a laser cut Chop Saw mount for the Dremel multi-tool on Instructables. You’ll find all the files you need for laser cutting including an adapter for switching between the Dremel hand tool itself and the flexible shaft attachment, depending on which version you are using. The thoroughly detailed assembly instructions are also peppered with tips (and supporting pics) on how to best manage the trickier steps will see you up and cutting in no time.

…and if you’re wondering what’s up with this Instructables creator’s screen name, HTMF stands for Having Too Much Fun! 

 

How To Make an All-Wooden Laser Cut Padlock

Keeping your treasures safe 

laser-cut-lock

Knowing that your valuables are securely locked away gives peace of mind, whether you are storing the jewellery inherited from your grandma or the secret plans to your Next Big Thing. Perhaps you just need to keep someone out of your private space, or to seal off the cupboard under the stairs from monsters that lurk in the dark.

Whatever the reason is, a lock and key can be handy indeed. So instead of heading down to your local hardware store to buy one, how about building a fully functional laser cut lock of your own?

This simple and clever design from Thingiverse user PArtzzles will prevent prying fingers from finding their way into your box of treasures. The design for the laser cut lock was worked out on Inkscape, and files are available to download so that you can make a version of your own at your favorite laser cutting service. Some makers might like to adapt the lock to further boost its security credibility to a level that will stop thieves in their tracks. Well… that’s the idea, at least!

via Thingiverse

How To Use Nesting Parts in Laser Cutting

A guide to laser cut line optimisation

ponoko-nesting-lines-example-laser-cut-cardboard-bin

Discussions around the laser cutters at Ponoko continue to highlight how important effective nesting of parts in laser cut files is. Today we are taking a look at a real-world example of how optimising linework can achieve faster cuts and therefore save money. Cutting time is generally the most expensive component when ordering from Ponoko. In the Ponoko forums, people have shared their methods of saving money. Let’s take a look at nesting line work in greater detail…

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This is the design we will work with – a bin. It is designed to take standard supermarket shopping bags, and was cut from 6mm thick double sided P3 corrugated cardboard. The first prototype came out to be about $40, an amount that could be considered a little steep for cardboard. However, after a few design changes we were able to reduce the cutting time by nearly half.

Design

First, consider good design as being the minimum necessary. The phrase “more is less” is a good mantra to abide by. Clever designers will figure out the best way to maximise the use of materials and processes they undergo.

Look carefully at your design, is there anything that could be considered superfluous? Is there anything that if you took it away, nobody would miss it terribly?

Curved lines vs. Straight lines

Keep in mind that lasers slow down dramatically on curves. If you ask yourself ‘are there any parts that you can take away curved sections without compromising the overall design?’ and the answer is ‘Yes’, then be sure to head back to your design program of choice before sending files to the laser cutter. Several vector drawing programs allow you to simplify linework down to straight lines. If not, try to reduce the size of radiuses as shown in the image below.

Another handy tip is that if you have lots of long straight lines try to align them parallel with either the x or y axis – this means the laser’s lens is only traveling in one direction at a time, it is slightly more efficient for the laser cutting.

Check the laser won’t see double

There can be an issue with overlapping linework. The laser doesn’t know what your intention was – it just thinks you want to cut the same line twice. It may sound obvious, but some vector drawing apps are more prone to this than others, it is often very easy to duplicate or copy and paste linework on top of each other.

You usually can’t see this, but the laser definitely can. In extreme cases this will double your cutting time (and cost) and increases the chances of burning the material. Always check your drawing files for duplicate linework.

The Fix: ungroup lines and drag the vertex points around to check you have no double ups.

Nesting cutting paths

Are there any parallel lines, or semi-parallel lines you can join to one another to make one section? This will give you greater control over the order of laser cutting parts. Remember to delete any shared lines that may double up.

You can see in the bin example below we had 12 individual strips, but then we changed the design to make them parallel on both sides and placed them together. The laser splits them after it has cut around the outside with individual parallel lines.

changes.jpg

Laser cutters don’t necessarily cut sequentially where you logically think they should. Sometimes they will travel to the other side of the material for the next line despite other linework in closer proximity.

Also, due to the slight unpredictability of the cutting order it can be helpful to upload several slightly differently nested files. Sometimes the placement of parts next to one another might help you save a few precious dollars or cents.

Experiment

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Different materials have different cutting speeds and characteristics. Feel free to post any tips you find on reducing cutting time on the support forums and in the comments below. There is much to learn from hearing other people’s experiences.

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Remember that it is unlikely your first design is going to be the best; prototyping is always an iterative process. Plan to make several variations of your design and do small tests so you don’t waste time, money and materials. As the results show here, a little tweaking of the design can save you a lot.

The content of this post by David McGahan originally appeared on the Ponoko Forums.

Ideas for Creative Agencies & Brands – #34

Themed ‘Build Your Own’ event kits

honeymoonkit0

Diy kits are a great way to engage people with the world that your brand inhabits. From a collection of snap-together laser cut parts, a miniature diorama can be created that entertains and stimulates playful conversation.

Connect to an event

The example here comes from Michiel Post van der Molen’s wedding, where guests were given a Build Your Own Honeymoon kit that enabled them to become immersed in the newlywed spirit. The package contained iconic laser cut silhouettes along with a felt base, where a grid of slots allowed personal interpretations of the ideal romantic getaway to be clipped into place.


honeymoonkit3

honeymooncollage2

Connecting with your brand

What unique worlds can be created to connect people with your brand using laser cutting from the Ponoko Personal Factory? Let us know in the comments below. By handing out simple, thoughtful construction kits to potential customers, there is an opportunity for them to become new storytellers and enthusiastic brand ambassadors. For more ideas for Agencies and Brands, see the other posts in the series.

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How To Make a Plaster Cast from a Laser Cut Mold

Giving traditional sculpture techniques a digital manufacturing makeover

lasercutplasterhead1

A plaster cast of your head is a great novelty, but the process of acquiring one has not traditionally been a pleasant experience. Thanks to a post by Koen Fraijman on Instructables, immortalising yourself with a sculpted bust just became a whole lot easier. How did he do it? By using laser cutting!

Scan and edit the 3D file

The process begins with a digitised scan of the subject – in this case, it’s Koen’s own head. A moderate understanding of the program Rhino is required for the next few steps, where a mold is built around the imported 3D scan. This is also the time to include locator holes, so that pins can be used to aid in lining everything up during assembly of the sliced model. Rhino’s Nest takes care of the slicing, and also prepares everything nicely for laser cutting.

It is important to choose materials carefully and make sure the layer height is correct before heading to the laser cutter. Koen decided on cardboard because it enabled a relatively easy cleanup process once the plaster was poured, and the cardboard flutes also give the model an interesting surface texture.

Cutting the sliced model

Once you’ve had all the elements laser cut at your local maker space or perhaps your Ponoko Personal Factory, the mold is ready to assemble. As a bonus, all of the inner segments that make up the void can also be stacked to give you an additional head sculpture!

lasercutplasterhead3

Pour, clean up and then stand proud…

Making plaster can get a bit messy, but there are plenty of tips on Instructables and Koen includes a few handy hints in his post. After a couple of hours, the plaster will be set and it is time to literally unbox your sculpture. Because the cardboard is brittle/soggy (when wet) and the plaster creeps into all the nooks and crannies that it can, the cleanup can be a bit laborious – but the results, as you’ll soon discover, are well worth it:

lasercutplasterhead2

A very distinctive permanent record of how you would look, should you be made of (in this case) corrugated cardboard! Koen’s key innovation of using laser cutting to create a mold for the plaster cast made this process quite different to the way molds are usually taken.

With the ease and accessibility of 3D printing in workshops across the globe, it is good to be reminded that some of the old stalwarts of model making and sculpture are still viable options… even if they have had a helping hand from a 3D scanner and laser cutter.

See the full process on how to make a plaster cast from a laser cut mold on Instructables.

 

How To Make The Most of your Laser Cutting Materials

Browser-based vector nesting tool optimises laser cut layouts

SVGNest

Fitting all of your laser cut parts so that they squish into the least possible area on your laser cutting template can be tricky. Most of us will approach this by trial-and-error, manually shifting objects around until it ‘looks about right’. While this will save a bit of laser time, with complex designs the process can be laborious and you can’t really know whether the layout you have chosen is the best possible solution.

That’s where clever software such as Jack Qiao’s SVG Nest can really come in handy.

What is SVG Nest?

Rivalling powerful (and expensive) commercial options, the freely available SVG Nest uses all the computing muscle your browser can throw at it to come up with the optimal layout for your laser cutting. By grouping all of the elements within a defined area, the geometry-driven genetic algorithm is able to find the best fit by first setting the largest shapes, and then working in the smaller objects around them. It gets really interesting when there are many many design elements, and also when the objects to be sorted are all of a similar size.

Here’s an example using laser cut lettering:

svgnest nesting

Why is this useful for laser cutting?

As we’ve previously outlined in the Top Ten Ways To Reduce Laser Cutting Costs, how you position your designs on the Ponoko template can really make a difference to your laser cutting pricing. One of the reasons for this is that the laser head has less distance to travel between each part, and as you are paying for laser time, minimising travel is an immediate cost saving. Another consideration is the material cost itself – minimising material wastage will also save you money. As an added bonus, being thrifty with your resources can make you feel good too!

For more information about SVG Nest head to Jack’s GIT repository, where you can also see a demo of the software in action. Just be warned, it is seriously CPU intensive so those on mobile devices might want to wait until they’re sitting in front of a harder hitting machine before trying it out.

via Just Add Sharks

How To Understand Vector vs Pixel Artwork

Beginner’s Guide to Digital Imaging Formats for Laser Cutting

vector-pixel-Ponoko-logo

One of the great things about laser cutting is that it makes high-quality outcomes both accessible and affordable. Some new users are happy to dive right in, but others need a little extra help in the early stages… and that’s what we are here for.

Before you get started it is a good idea to familiarise yourself with some of the basic knowledge and terminology associated with laser cutting. Understanding image formats used in the preparation of artwork for laser cutting is one of the common hurdles that newcomers face.

Let’s take a look at the difference between Vector and Pixel artwork, and what this means for laser cutting.

First up: Pixels

Bitmap images use a grid of ‘Picture Elements’ (pixels), each with a specific set of information. This is a fantastic choice when creating or editing images because there is a high level of control over tones, textures and colors. The sensor in a digital camera records information in this way, and image editing programs such as Photoshop use pixels to work their magic.
Common file types: TIFF (.tif), BMP (.bmp), GIF (.gif), JPEG (.jpg).

Pixels: the good

The upside of pixel-based images is that you have such great control that allows you to replicate all the color and detail of the physical world, and so long as you have the original data, edit to your heart’s content.

Pixels: the bad

Image size. Because data is being recorded for every single pixel, as images get larger, so too does the amount of information needed to define the image. Larger file sizes means more storage space required, and more computing power to process the extra information. Also, Pixel-based images do not scale well. While they can be reduced in size, doing so will result in permanent data loss. This means that image quality will suffer if you try to increase the pixel dimensions, because the computer has to guess how to fill the extra space now that the data is no longer available.

Vector Images

Vectors are best known for their use in typography, drawings and graphic art such as logos. The way that images are created using Vectors is quite different from Pixels. Vector graphics are defined by mathematical equations – they take points, connect them with lines in various shapes, then fill with a color or gradient range. To achieve more complex shapes, there would simply be more and more points and lines. Programs such as Illustrator and Inkscape work with Vectors to create images.
File types: Encapsulated Post Script (.eps), Adobe Illustrator (.ai), Scalable Vector Graphics (.svg).

Vectors: the good

The big thing about Vectors is that they are scalable. No matter how close you get, vector artwork will always be crisp and sharp – independent of the image resolution. The same information (and the same sized Vector image file) can be used to draw a circle whether it is 1mm across or big enough to feature on a billboard. File sizes remain small, regardless of the scale of the image.

Vectors: the bad

There is one notable disadvantage with Vectors; they are not well suited to creating photographic images. This is because the volume of information would become so large as to work against the strengths of using the Vector format.

How does laser cutting fit in?

For laser cutting, Vector paths make the most sense because they are using a more efficient way to get the desired result. When it comes to laser engraving, things do start to change. Laser cutters are happy for engraved images to be either Vector or Pixel-based, but it is important to keep in mind that laser time is expensive. A simple logo might take 3 seconds to engrave as a vector outline, whereas the same object as a Pixel image could take 10x as long. This is because to engrave the Pixel version, the laser has to move across the whole image area from top to bottom; a greater distance than tracing the actual linework itself.

So now we know that Vectors are defined conceptually, in a mathematical space, whereas Pixels exist in a literal space within physical confines. The key difference that results from this is that vectors operate independently from the image resolution, and can allow for more cost-effective laser cutting. Pixel images enable a more detailed, photographic outcome – but this comes at a cost in terms of file size and (importantly for laser cutting) time in the laser cutter.

Here’s a video you can watch that helps clear up some of the mystery when it comes to understanding vector and pixel artwork.

How To Make Laser Cut Interlocking Acrylic Designs

The Importance of Radii

We’ve written about using ‘nodes’ with 3D objects made from wood before, but suggested it may not work for acrylic because it is more brittle and tends to be less forgiving.

However, after working with Drownspire to develop their Vambit toy into a product for a giveaway at Makerfaire, it soon became apparent that you can successfully use nodes when making with acrylic.

Nodes in Acrylic: Two tricks to getting it right

Firstly the nodes need to be a bit smaller; something in the realm of <0.15mm/0.006″ on each side. This means they won’t cover the same range as when used in wood but they still remain a good option.

Secondly, how you treat the end of the slot is the key. If you have a sharp corner, which is typical in a laser cut slot, the acrylic will always fracture at that point. See this example:

Effectively a sharp corner is creating a weak point in the acrylic. Not such a good thing when this is an important structural part of the design! A small radius in that corner can do wonders to transfer the forces from one face of the hole or slot to the other, and reduces the risk of the material splitting at the corner.

How large should they be?

The larger the radii the stronger it will be so you will need to make an aesthetic decision on how big you can go. On the Vambit the radii was tiny, at just 0.26mm, and it was enough to make a noticeable difference. We suggest aiming for 0.5mm and greater if your design will allow it.

Where to place the nodes

Another trick to keep in mind is putting the nodes on a part of the design where you can guarantee the length. That way you don’t need to bet on the thickness changing and the range of variation is a lot smaller. This occurs when you have 2 edges that are cut by the laser that are the friction edges. This works if you are using tabs but is not necessarily the case if you are using a slotting joint.

For example, in the design of this spinning top Dan put the nodes on the tab as opposed to on the slot.

The tabs on the triangle parts fit into the slots on the circle part. Dimension X and Y will be the same each time as cut by the laser, therefore he put the nodes on these parts. Had the nodes been positioned on the slot for the handle (as in diagram below), the friction points would be against the surface of the material, a part that can vary if the thickness varies.

Other types of connections

An alternative joint is the t-slot joint which is popular with people who make more engineering-type products. This joint uses tabs to locate pieces then a t-shaped slot with a captive nut. This type of joint is great. You can slightly oversize the holes to allow for oversized material and the bolt will hold it snug together. If you use the radii on the corners of the cut outs you greatly reduce the risk of cracking the acrylic by over tightening the bolt.

If you want to go another step, rubber washers can also reduce the chance of over tightening and maintain tension in the bolt so it won’t come undone through vibrations etc.

Hopefully these tips will help you with your next laser cutting project, or perhaps give you the extra tools you need to finalize a design you’re working on.

We’ll be interested to hear your experiences using radii too, and any other advice you might have for people wanting to make 3D designs using acrylic. Let us know below!

This handy advice from Dan Emery was sourced from the Ponoko Support Forums.

Ideas for Creative Agencies & Brands – #26

Cool Conference Swag You Could Laser Cut For Pennies!

Packing for a conference is a lot like packing for a hike.

You have to pack the essentials, you want to pack a few standby items and you’d like to bring certain vanity items along, just for the heck of it. But as you pack, you also need to keep a check on the weight of your pack. Plus, unlike a hike where you probably won’t encounter more than one or two people at most, a conference is full of people who are eager to hand you bags of stuff!

Yet before you begin rummaging through conference bags for stuff to keep, here’s a quick list of things most attendees wish they had brought along which can be laser cut really cheap.

Simple Conversation Starters.

Lasercutwristband

Laser Cut Wristbands.
While you will do your best to network before the session and during the breakout periods, the fact is you won’t be able to approach as many people as you’d like. But rather than rush through conversations with multiple people, you can use a little laser cut panache to draw people to you.

If designed well, this is bound to get you noticed even when you do something as simple as answer a phone call. It also helps you stand out in a crowd by acting as a distinct visual marker. Within a conference setting, you get instantly noticed if you have to raise your hand. And finally, it can be a great way to share your personal details without having to repeat them over and over (just in case your name or email has a complex spelling). Plus, if you run out of business cards, or don’t feel the need to share a business card with certain people … you can redirect them to your wristband for your details instead of the awkward fumble for a pen and napkin.

Things That Make You Memorable.

lasercutbusinesscard

Laser Cut Business Cards.
Getting noticed is only half the battle. Your next step is to leave a lasting impression on your new acquaintances. Here are some easy to produce laser cut items, which can do the trick.      (more…)

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