If you like this instructable, check out my other 3D printed creations on my other instructables or on my website.

It has been said before that the simplest inventions are usually the best, such a the lightbulb, and the cup... and I am here today to re-design the latter, the cup, and talk you through the process the whole way from concept to design (then to reality if you own a 3D printer) for all abilities of CAD (computer aided design) modelling skills (designed using AutoDesk's free CAD software 'AutoDesk 123D Design')...

First let's start with an impressive statistic: over 100 million people drink coffee EVERY morning in America alone, that means even more drink any hot beverages including tea and hot chocolate at least once a week, this introduces the need for a cup that's suitable for all the problems of drinking hot drinks.

First Problem:
Let me introduce the first problem with cups (including mugs), they cause hot drinks to cool down rather quickly as they are not very insulating, this makes the need for an invention for something to keep hot drinks hotter for longer necessary so hot drinks can be enjoyed over a longer time without going cold... Yes, I know, that has already been invented, it's called a vacuum flask which is sold under many names such as the Thermos® Flask. This quite ingenious invention solves this problem by taking into account all three ways of heat loss from the drink: conduction, convection and radiation by having the drink surrounded by a silvered container separated by a vacuum, the vacuum prevents conduction and convection and the reflective surface of the silvered container prevents heat loss via radiation.

Second Problem:
The second problem that arises when having hot drinks is essentially the opposite of the first, many hot drinks such as coffee are required to be made with boiling water and this introduces the problem that boiling water is too hot to drink and it can take a long time for a drink to cool down to a suitable drinkable temperature before we can drink it resulting in the inpatient of us and those of us on a tight schedule burning our tongues and throats. This problem is ironically worse when we attempt to solve the first problem of hot drinks cooling too quickly by using a product such as a vacuum flask which slows down the rate of cooling of the hot drink, this means more time is needed before a boiling hot drink reaches a suitable drinking temperature and can be drunk. So what can be done to solve both problems?...

Coming up with a solution:
When I realised these two problems, I realised it would be almost impossible to create a cup to solve both as the required features are opposite, a cup that first cools the boiling hot drink to a drinkable temperature but then keeps it hot for as long as possible so it can be enjoyed for longer.
So to summarise, the cup must quickly lose heat from the drink but then prevent this happening once it has reached a drinkable temperature...

So here is my solution...

Step 1: The Solution

The Solution: Variable Insulating Cup
My idea is to change the insulating properties of a cup while it is in use by taking advantage of two of the three methods of heat loss, conduction and convection, by allowing the user to switch between two selectable modes that affect the insulating characteristics of the cup depending on their need...

High Insulating Mode:
To first solve the first problem of drinks cooling down too quickly, I have prevented heat loss through conduction and convection by designing a unique double walled cup design (which is very well suited towards being 3D printed), similar to that of a vacuum flask however instead of a vacuum, the cup traps 5mm of air in between the inside surface of the cup and the outside surface acting as a very effective insulator. Air is one of the best insulators and it is used as the main insulator in nearly all types of insulation by utilising trapping air such as wool and styrofoam. Did you know that many indoor ski slopes are kept cool by being insulated in a very similar manner to my double walled cup design by having a layer of air between the internal walls and the external walls keeping the the ski slope cold.

Low Insulating (heat loss) Mode:
To solve the second problem of drinks staying too hot for too long when they are first made, I utilise the methods of heat transfer by both conduction and convection to draw heat away from the cup as quick as possible. By simply rotating the ring at the top, this opens vents at the top of the outer layer of the cup allowing air to circulate through the vents at the bottom and the open vents at the top circulating air in the cavity in-between the inner and outer walls of the cup. Due to the hot drink heating up the air in the cavity between the two walls, this causes this air to be less dense and lighter that the surrounding ambient air making a convection current by causing this air to rise up and out through the top vents from between the cup's walls due to its lower density and causes cold air to be drawn in through the bottom vents and this cold air is then heated up by the drink and the cycle starts again which ultimately draws heat away from the drink efficiently.

Next is to test this concept in the real world to find out if it would work as expected and to what extent it would work...
Id put a patent on your idea before some rich guy tries to steal your idea. Great job, keep it yours!
Thanks!!! Unfortunately patents are many thousands of pounds (in the UK) and this is money I don't really have to spend unlike 'rich guys', if there was a cheap easy way to protect the idea (similar to copyright which is automatically created upon the creation of a document) I would do so... I'm glad you like the idea though :)
What you need to do is get a patent pending on your idea. Patent pending is very inexpensive and you have a year to patent it. Ultimately you can protect your idea until you can generate enough revenue to patent it. From my understanding to patent pend it is usually around $100 USD
What a neat idea. Love that you tested it so well! <br /> <br />Really clear instructions for making it, too! :D
Thanks, I'm glad you like it :)
<p>my homemade CNC</p><p><a href="http://www.linkbucks.com/4258f063" rel="nofollow">http://www.linkbucks.com/4258f063</a></p>
<p>Very well written instructable, and such a great idea! I didn't know about AutoDesk 123D Design. I've always made do with Google Sketchup. Thanks for sharing and good luck!</p>
Thanks :)
Wow, awesome design, I can definitely see this being used everywhere all the time! Congratulations!
Thank You :) I hope so
Congratulations on winning. I really liked your project. Now all we need to do is combine both of our projects to make the ultimate cup!
Thanks!!! Yeah if we joined forces we could take over the cup market!!! I liked your design btw, very inventive and useful :)
I'm not sure how great this will work. Although i think this is a great idea, i dont think that anything will be able to force air to flow through the vents. i think all that will happen is hair just getting trapped. i think that the best thing to do would be to add a fan on thae bottom that will force air through the vents, well anyway best of luck.
As shown in step 2 where I test the idea http://www.instructables.com/id/Variable-Insulating-Cup-Convection-Cup/step2/Concept-Testing/ this concept does work well, the numbers don't lie. When the top vents are open, passive convection currents are generated because of simple physics by the hotter air in the cavity being less dense, air doesn't need to be forced through the vents, the hotter less dense air in the cavity literally floats out of the top vents creating low pressure at the bottom pulling in cool air through the bottom vents. Thanks anyway :)
Does it really work or is the video and graph just for presentation? I noticed you didn't show your cup in the testing video.
I promise you that it does really work, all the data on this instructable is genuinely taken from myself testing the cup with the vents open, closed and then open until 50C then closed thereafter. The thermometer was placed in the hole in the lid of the cup (you can see the hole in the lid on the pictures), the cup was not visable in the video because if I placed my ipad that far away I wouldn't be able to read the temperature as easily (and when I took it I didn't think I would be presenting the time lapse in a instructable), if you don't believe me you can plot the temperature curves yourself using each time lapse (each frame is 30s apart, the total time testing each scenario was 30 mins giving 60 readings to be plotted per scenario, I typed in 180 readings in total into Microsoft excel to create the graph) and you will discover you will have an identical graph to mine.
To add a bit more perspective I added my hand to the setup...
Here's the setup of the thermometer and cup I used to measure the temperature so you can visualize it better...
You also can't patent an idea once it has been in the public domain. A friend at school didn't know this and entered his product into a competition before patenting it. Your mug is a good idea though!
Well at least some rich guy can't do it instead then, cheers!
How do those squares feel on your lip when you drink out this cup?
I actually don't know as I haven't been able to make it yet, but if it is uncomfortable, I can always use the 'fillet' tool to round these edges if they are an issue.

About This Instructable


73 favorites


More by Maundy: Variable Insulating Cup - Convection Cup 3D Printing Moving Parts Fully Assembled - 28-Geared Cube 3D Printed 'Centrifugal Puzzle Box' - solved with a spin...
Add instructable to: