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Injection Moulding Christmas Decorations

As we are entering the depths of the festive season, we felt it appropriate to have a blogpost or two with a seasonal theme. The principles of this post however, will be applicable any time of the year.

We are going to be using our injection moulding kit to make some Christmas-themed tree decorations and fridge magnets. For those of you unfamiliar with the kit, it can be used to teach the basic principles of injection moulding, but at a very low cost compared to commercial equipment. You create a 2D mould by either lasercutting a material e.g MDF or acrylic, or by bending a thin aluminium strip. Once this is sandwiched in between the two large plates, you can inject it with a thermoplastic – in our case, coloured hot-melt glue. This method means that basic injection moulding is achievable by all, and on a low-budget.

Without further ado let’s get into our project! First of all, we need to think about what is is we are trying to make. As it is nearing Christmas, we wanted to go for something festive. We decided on making tree decorations/ fridge magnets. The principles for our moulds will be pretty much identical.

To start with, we are going to make a Christmas tree-shaped mould, using the aluminium strip. We measured our maximum working dimensions, and planned a tree-shape within that range.

We then set to work creating our mould. It’s a good idea to turn on your glue gun now, if you can keep it in a safe place, so that it is ready to use when you’ve finished your mould. We need to bend the aluminium strip into our required shape. This can be made much more difficult than it needs to be. The main thing to remember, is to start near the end of your strip, so you aren’t trying to bend it in on itself too much. We modelled our shape using ‘sheet metal’ mode in Fusion 360. The great thing with this, is that we can unfold our model, and create a template. But you could easily print out a template and mark out where you need to bend the metal.

Once you have your mould, you need to place it inside the outer case. Don’t forget to place it so that the injection hole is within your desired shape. It also helps to slightly grease the mould, to allow the glue to separate from the case/mould. We’ve placed a small magnet inside the mould, and held it in place with another magnet on the outside.

*Note that we have made a clear acrylic top plate, to make it easier to see whats happening inside.*

Once you’ve screwed the top plate of the mould on, double check that there aren’t any gaps, and that the case isn’t bowing. You may find it easier to place the ‘wings’ of the mould plates the same way, so when you screw them together, they hold the wire frame tighter. This is especially useful if you can’t quite get your mould to sit flat.

The other method for mould making, is to laser cut a piece to go in between the plates, to replace the bent wire. This time, we’ll make a snowflake tree decoration.

Once designed and cut, follow the same steps as before, to create your object.

You can then either glue some string to the decoration, of pierce a hole in the top, and pass some thread/wire through.

And there you have it, your very own DIY injection moulded Christmas decorations.

If you have a go at this project, or any other, we’d love to see! Get in contact with us via email, or on FacebookTwitter or Instagram

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New and Improved Slinky Seismometer

After many months of work, research and discussions, the latest iteration of our Slinky Seismometer Kit is now available. We’ve taken feedback from customers, and worked closely with Paul Denton, who has over 30 years’ experience in geophysics and education, to drastically improve the Slinky Seismometer Kit.

For those of you unfamiliar with the device, here is an excerpt from the description:

“Originally designed in association with the British Geological Survey (and Paul himself), our new and improved Slinky Seismometer Kit provides an elegant and low-cost solution to earthquake detection. The seismometer uses electromagnetic induction to detect ground motion and incorporates eddy current damping for improved sensing. Supplied in kit form, the seismometer is quick and easy to assemble, and you’ll be up and running in no time!”

We’ve taken the time to improve our original slinky kit, and as such there are a host of new and improved features. We’ve changed the outer casing to an engraved, rigid acrylic tube, which provides more stability and protection to the device.

We have an adjustable threaded top, for height adjustment of the magnet inside the coil.

There are now three adjustable threaded knurled feet, which allow you to easily centre the magnet inside of the coil.

Furthermore, we now have a dual coil assembly, with a 14mm magnet balanced between them. The coils have opposing directions, but are wired so that the detected voltage is cumulative. This allows for a greater sensitivity in readings but any interference is cancelled out.

As with our Build your own Seismometer Kit, we now have a small PCB with a 3.5mm jack socket, which allows for easy connections to your chosen seismometer interface.

The kit is available to purchase now, and for a limited time you can get a SeismicPi HAT, worth £48, for free! Just add the ‘Slinky Seismometer Kit‘, or the ‘Build your own Seismometer Kit‘ to your basket and enter the coupon code ‘EDUSEIS1’. Your free SeismicPi HAT will be added.

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Redfern and the Global STEM Award at New Scientist Live

Next month, Redfern along with the Global STEM Award are heading to New Scientist Live, at the Excel Arena in London.

Global STEM Award, in partnership with Redfern Electronics are bringing a range of exciting projects to the show. Redfern will be showcasing space-themed robotics activities and investigations with the opportunity to test your ‘Crumble’ micro-controller coding skills. The Global STEM Award recognises the completion of STEM projects by 9 – 13 yr olds.  It is the only scheme through which candidates develop an awareness for both their world AND the careers of the people who make these amazing things happen in real life. The Redfern activities are accredited for use towards your Global STEM Award.

Show Launches – Two new Global STEM books and boxes will be unveiled at the show (EXPLORER and CONSERVATION routes). These are ideal for STEM clubs or home educator groups. The boxes contain all you need to run the activities and certificates for Bronze, Silver and Gold awards.

Crumble kits – Redfern Electronics will be offering Crumble kits, at special show prices, containing all the parts necessary for a range of projects. Accredited by the Global STEM Award, each box also contains a voucher to get you started on your awards journey.

Special show offer – Bring your completed Global STEM Award projects with you (photos and/or project sheets). We would love to see them and you can purchase your Bronze/Silver or Gold Awards at the stand for a 25% show discount. All the award information is on the website and you’re welcome to contact us with any questions.

And a bit about us…

Global STEM Award was founded in 2017 by UKSTEM and launched officially in 2018. With key STEM partners of Redfern and the University of Wolverhampton, the award has found plenty of recognition. It was quickly adopted as an entry route into the Big Bang Competition and has been accredited by Children’s University. The Global STEM Award is currently available at 3 levels: Bronze, Silver and Gold, with a Platinum level, for older learners, planned for launch in 2020.

Since Redfern Electronics launched the Crumble controller in 2014, the Crumble has grown from strength to strength, becoming a staple of physical computing in the UK. Redfern is now applying its philosophy of accessible and affordable products into new areas of STEM. Partnering with the Global STEM award fits perfectly with their exciting new direction.