Tuesday, 22 October 2013

Busy and Exciting Times Ahead for the Freedman Chair

The Freedman Chair is set to break records on Kickstarter.

After such a successful launch, predicted to be the most funded UK Kickstarter campaign to date, the go ahead was given to start the manufacturing process.

JNDC have been working with Simon Freedman, an osteopath and inventor, for over two years. The process has involved the engineering design, development and prototyping of the chair. The work is far from complete and the next stage, the manufacturing process, is now in full swing.

Kickstarter Updates:


Monday, 21 October 2013

The Freedman Chair, a better way to sit - A hit on Kickstarter

Just under £100,000 pledged in the first 3 days on Kickstarter!

Kickstarter is a new way to fund creative projects. Each project is independently initiated. Project creators set a funding goal and deadline. If people like it they can pledge money to make the project happen. Projects must then reach their funding goal to go ahead.

Created by osteopath and inventor Simon Freedman and engineered by JNDC Ltd; this is the only chair in the world designed to maintain your standing posture.

Simon's Story:

I'm an osteopath and inventor who set out to find a solution for my patient's problems and make a chair that was comfortable. I've been lucky enough to gather a fantastic team to help me along the way.

More and more patients were coming in to see me with aches and pains associated with sitting and I just couldn't find a chair that helped. I began to think that there must be something wrong with sitting itself, so I immersed myself in the subject. My research led me to the conclusion - we are just not meant to sit. It's a theory that's really hitting the press at the moment. I've been working on a solution for my patients of 18 years and I believe my chair will solve a lot of people's problems.

I set out to make a chair that helps the spine and pelvis achieve the same position in the sitting as when standing. I've devoted 26 years, as an osteopath, to looking after people and solving their problems. I know it probably sounds a a bit naive, but I really do want to make a difference to people's lives. I believe that The Freedman Chair will make you more comfortable, healthier and fitter than any other chair. It may even save your life.

Click the link below to see how the project is progressing :

Engineering Design Consultants:

Thursday, 17 October 2013

Crack Propagation Analysis

Adhesive joints are increasingly used in various industries from aerospace to civil. They allow complex shapes to be joined and they also reduce the weight of the structure. Because of this composite materials are often bonded. Composite materials are very anisotropic, in the fibre direction they are strong and stiff however their transverse and shear properties are low. Bonded joints experience peel loading, so the most likely mode of failure is in the transverse direction either in the adhesive or the composite itself.
It is therefore important to study the joints to find reliable methodology to predict the strength of the adhesively bonded composite joints.

A finite element cohesive zone model (CZM) was modelled to predict the peel strength of the joint.
The most widely used method of determining mode I interlaminar fracture toughness (peel strength) of a bonded composite joint is the double cantilever beam (DCB) test [1]. The method is based in linear-elastic fracture mechanics theory [2] and calculates GI using the crack length as well as the applied load, load point displacement crack and initial specimen width. 

Figure 1. Dis-bonding

Figure 2. The load/ displacement curves

The predictions of the model have been compared to the experimental data. Fig 1. shows the process of dis-bonding in the model. The load/displacement curves show a good agreement between the numerical prediction and the experimental result as shown in Fig 2.

1 D5528-01 (2008) Standard test method for mode I interlaminar fracture toughness of unidirectional fibre-reinforced polymer matrix composites. Annual Book of ASTM Standards 15.03.
2 Griffith A.A. (1920) The phenomena of rupture and flow in solids. Philosophical Transactions of the Royal Society of London 221(21): 163-198.

YouTube Video Link:


Friday, 4 October 2013

Pre-production Prototype Case Study - The chair that could save you life

JNDC previously designed and manufactured two series of prototype seats to undertake extensive research and development in relation to ergonomics.  Following the completion of the second round of prototyping the customer instructed JNDC to undertake design for manufacture as well as the manufacture of 5 "pre production" prototypes.

Moving from a detailed prototype to a final pre-production prototype required JNDC to revisit every part to optimise for manufacture.  Weight, cost, manufacturability as well as the overall look and feel of the chair had to be considered.  In addition, advanced prototyping techniques had to be selected to mimic a final manufactured part, without going to the expense of investing in expensive tooling.
Sand casting, silicone moulding as well as CNC milling and turning were the key processes used to develop the 5 pre-production prototypes.  JNDC coordinated the manufacture of all parts, and when complete undertook the complete assembly process in house to ensure the quality of the final product met and exceeded the customer's expectations.

Next Steps
The prototypes are now being used for marketing, from trade shows to photo and video shoots through to pitching to potential distributors and buyers.  The preproduction prototypes will also be used to receive accurate quotes from manufacturers, allowing the companies to see the physical items that they will be manufacturing in high volume.

Wednesday, 2 October 2013

Will Polymorph Help Reduce the Time to Manufacture Sand Cast Aluminium Parts???

Over the weekend I was thinking about the parts that we get printed here at work in ABS which are then sent to the sand casting foundry to get the parts back all in the same day.

I was trying to work out what would make the process quicker, and also lower cost.
Up to now, I have been printing the parts out and then the foundry adds in gates, risers and sprues etc to allow the aluminium to enter the parts at the correct location.
Now that I have done this a few times, I was thinking about sending my next parts to the foundry already with the gates etc on the part, therefore very low preparation required by the foundry and ultimately saving cost and time!

First I thought of adding the gates etc into the CAD model and have the part printed ready to go, but then I realised this would take up my time doing the CAD and also use up our precious material for the printer... and the printer would take longer to print. 

Then I remembered, a year or so ago I discovered a thermoplastic called Polymorph.  It comes in small grains (about the size of rice) and you pour it into boiling water.  Within a few seconds it goes clear, then after draining the water out, you have about 2 mins of working time to shape it into whatever shape you need. When it cools, it is rock hard.

Here is a picture of what's needed.  (Cup of boiling water, printed part and Polymorph)

polymorph to manufacture sand cast aluminium parts

Polymorph in the water

Prototyping engineering design

And here it is about 30 seconds after being in the water (you know it is ready when its gone completely clear)
Prototyping engineering design analysis

This next photo shows my first attempt that's not exactly perfect for casting, but you can see what I am trying to do. 

This photo shows the part now the polymorph has cooled.

Now the polymorph is hard, you can see what I am trying to do, essentially to give the foundry a rapid prototyped part ready to be put in the sand. 

It's just an idea I had, so if anyone has any thoughts and ideas I would really appreciate the help & feedback.