More Delcam

This weeks brief was to create CNC code which made use of two different tools, the 4 and 6 mm flat drill bits. To do this, a model was created and Delcam was used to plot the features and tool paths. The paths Delcam created were then edited to use the 4 and 6 mm bits only. The 6 mm bit was mainly used for the rough cuts and the face cut, as this larger bit reduced the overall time for the completed block. The 4 mm bit was used for the finishing cuts and any cuts that needed a finer tool such as the narrow circle cut in the “Cross Block.”

The Roland CNC machine does not have an automatic tool change function, the tool need to be changed manually. Delcam creates code which assumes the tools change automatically, therefore, the code needs to be edited further before transferring to the Roland CNC machine. The tool paths are arrange so that the same tools are grouped together, and then one tool path is suppressed (in this case the finishing tool path was suppressed, leaving the rough pass running). Delcam then only displays the CNC code for the running tool path. This code is copied into a text file and saved appropriately. This process is repeated for the finishing tool path, and the code copied into a separate text file.

This method generates several text files depending on the number of tools used, in this case two. The files can be loaded into the CNC machine an run, one at a time, to achieve the desired model.

Delcam machining simulation

Block design

Cross Block

Delcam simulation

New Product Introduction (NPI)

New product development  (NPD) and introduction is the process of from initial product concept to production and introduction to the market. The development of new products can be broken down into four stages: concept generation, testing and refinement, prototyping and production (IdustryForum.co.uk, 2015). In an ever increasingly digital world, the technology and industry tools available are having an influence on each of these stages.

Expanded four stage NPD (Trott, 2005).

Shorter development timescale now exist thanks to developments in design tools and communication links and working practises.

Low cost prototyping is possible thanks to the developments and reduced cost of 3d printers, widely available CNC machines and computer aided design (CAD) packages.

More accurate manufacturing methods now exist, reducing manufacturing waste and increasing product quality.

Research and Development – Concept Generation.

Concept generation usually begins with a set of customer needs, a brief or the realization of a gap in the market.

“A product concept is an approximate description of the new technology, working principles and form of the product” (Ulrich and Eppinger, 2004, p.98).

New products that fail to research the market or customer needs rarely succeed and usually costly. The increasing popularity of NPI engineering and practises aim to help streamline the concept development stage. Taking into account research and subproblems that may stem from the original brief for the concept, whilst planning various review stages to provide constructive feedback and help keep the project on track. There are many various theories and methods designed to organise the concept generation phase, one such example is the five step method (Ulrich and Eppinger, 2004).

Five step concept generation method (Ulrich and Eppinger, 2004).

The five stages aim to gather customer and market information on the problem/brief before analyzing this data to generate feedback and ideas for new products/concepts.

References:

Industryforum.co.uk, (2016). New Product Introduction – Industry Forum. [online] Available at: https://www.industryforum.co.uk/expertise/new-product-introduction/ [Accessed 23 Feb. 2016].

Trott, P. (2005). Innovation management and new product development. Upper Saddle River, NJ: Financial Times Prentice Hall.

Ulrich, K. and Eppinger, S. (2004). Product design and development. Boston: McGraw-Hill/Irwin.

Delcam for SolidWorks

Using SolidWorks 2015 I designed a 100 x 100 mm block with several features and a facing cut.

The shapes are different depths

Isometric view

Using Delcam for SolidWorks, the CNC code was generated and a simulation of the cutting machine run. There was a little trouble with the rough cuts for the two circles, due to the width of the circles and the size of the selected cutting tool. This issue was sorted by manually overriding the finishing allowance from 1.25 mm to 0.25 mm.

The code was programmed to cut all features using a 4 mm drill bit. This code was generated for a Roland RotoCAMM CNC machine and contained 495 lines of code.

The CNC machine in action

The finished block

The design was cut into a 100 x 100 x 52.5 mm foam block (recycled from another student, hence the extra few cuts). The final block measures 100 x 100 x 50 mm thanks to the face cut which removes the top 2.5 mm of material.

Frequency Analysis

Ever seen the Chladni Plates experiment?

Using SolidWorks, we can analyse a square or circular plate to find the frequencies these patterns will occur.

The areas in blue in the above picture are those in which the salt or sand in the video would gather, they are areas of least movement. Here the sound waves are cancelling each other creating a node. The areas in red are the opposite, here the sound waves are interfering and combining to give a larger amplitude, forcing the sand to vibrate and settle in the blue areas.

If we change the material of the plate, say from plastic to metal, the frequencies of these modes will change.

Frequency ∝ √(Elastic modulus/density)

This relationship is 3.5 times larger in the metal, meaning the modal frequencies should be 3.5 times larger.

Plastic plate modes

Metal plate modes

The results aren’t exact, but near to the expected results. This discrepancy could come from the applying of a new mesh, when changing the material study.

Programmable Logic Controllers

Programmable Logic Controllers (PLC) are microprocessor based control systems capable of processing multiple inputs and outputs in order to control machines and industrial functions. With a programmable memory designed to be used easily by engineers with little knowledge of computer language, PLCs operate using a logic language (if A or B is true THEN output C etc). A user will programme the PLC for a given function, the PLC will then monitor the inputs (sensors, switches) and outputs (actuators) according to the program.

PLC block diagram (Bolton, 2009).

First developed in the 1960s, modern PLCs are available in small single units, to larger modular units capable of supporting many numbers of inputs and outputs. Many systems have the ability to be expanded by linking additional units together.

Siemens LOGO! 8

Modular unit, Nexgenie 5000 PLC

PLCs are designed to be installed in industrial environments and as such, they are usually rugged, well packaged devices so that they are able to withstand vibration, temperature, humidity and noise.

 

References

Bolton, W. (2009). Programmable logic controllers. Oxford: Newnes.

Crispin, A. (1997). Programmable logic controllers and their engineering applications. London: McGraw-Hill.

Mall.industry.siemens.com, (2016). LOGO! logic module – Industry Mall – Siemens WW. [online] Available at: https://mall.industry.siemens.com/mall/en/ww/catalog/products/5000562?activeTab=order&regionUrl=/ [Accessed 12 Feb. 2016].

Mitsubishielectric.in, (2013). Advanced Modular PLC by Mitsubishi Electric India. [online] Available at: http://www.mitsubishielectric.in/fa/fa-advanced-modular-plc.php [Accessed 12 Feb. 2016].

Concorde Visit

The IMechE arranged a visit to the Manchester Airport Visitor Centre, in order to have a tour of the Concorde they house there.

Not knowing that much about Concorde prior to the trip, I came away with various facts and figures and the conclusion that Concorde was a huge engineering feat, something Britain and France should be very proud of.

A 1970s supersonic plane using 1950s subsonic engines to travel at a normal cruising speed of 1300 MPH at a heigh of 40,000+ feet. A top speed only limited by the skin temperature of the plane. Once the temperature on the nose reached 123 degrees C, the pilot would have to decelerate.

At these great speeds the centre of gravity would move so far towards the tail, the flight engineer would have to constantly move fuel between the tanks under the wing to the extra tank under the tail.

One tone of fuel needed per passenger. The engines were fitted with afterburners, something no other commercial passenger plane has.

Leather Rolls Royce blue seats coasting £16000 to design, make and install.

Booking a seat on Concorde would cost around £7000, 20% refunded if Concorde didn’t make the stated ETA of your destination.

 

 

 

 

 

 

 

 

12 fuel tanks located under the wings

The 13th fuel tank is positioned under the tail

Expensive seats!!

Before the age of computing, this is what your cockpit looked like.

The Roll Royce engines. Special flaps to control the speed of incoming air would be lowered when travelling at sonic speeds.

Clam shells on the exhausts direct thrust. When these shells close thrust acts in reverse, slowing the plane on the runway.

Bracket Design and Analysis

Brief

Company has provided a rough sketch of their flower basket bracket and would like some analysis performed to test whether the design is feasible.

Rough sketch

The distance to the hanging load, A, was determined to be around 300 mm, allowing for the radius of the basket and clearance from the wall.

The chosen bracket material: mild steel

Testing

The weight of the basket tested was 12 Kg. The bracket’s performance was poor.

Bracket yields close to wall fixing.

Bracket not strong enough to support load and is displaced significantly.

To improve upon the client’s design, without altering the original significantly, a support was added. The mild steel still yields under load, however.

Bracket now yields along middle section.

Displacement is reduced in this design.

Conclusion

The design supplied by the client is not suitable for the hanging of a flower basket. A completely new design is needed.