Introduction: Tabprotec, Retractable Craft and Educational Device

Support the project:

*Please support my work and the project by voting for it in the in motion project.* By clicking the vote button at the top of this page. If I won any of the 3D hubs vouchers, I would love to spend them on getting the product printed to a higher quality out of ABS possibly.

Introduction:

See later stages for full Fusion 360 Files (Bonus points)

This is a project I have been working on over the last few months for my AS Product Design Coursework at College. The design concept came after working with a local school teacher who I wanted to create an innovative product for that would help in teaching Nursery classes (4-5 Year old children).

Tabprotec is an innovative design made out of 3D printed PLA which houses a sublimated PVC cloth that expands and can be retracted back inside the body once used. The product enables the teachers to perform craft lessons and interactive messy play in a quicker and easier structure.

Step 1: Design Ideas

The product is designed to attach on the width of a standard school table allowing a roll of oil-cloth vinyl table protector to put out and cover the table surface. This aims to function an easy to use, quick solution to setting up messy play activities in a pre-school environment.

The product features a simple minimalist design for the bodywork to help reduce the impact it has on the classrooms aesthetic. The roles of vinyl then being printed with custom designs such as handwriting guides, maps, cartoon animals etc.

With my product being for a school teacher the product must be affordable on a school budget. Costing between £50-£75 when produced industrially.

In a school environment interaction and active learning are important for the children and as my client mentioned in the client interview. With the consumer being 4-5 years old the product needs have safety taken into account, hence the clip to secure the product to the table and rounded design.

As well as saving time and resources for the school the product would reduce the use of waste paper. Such as newspaper which would if wet or painted on get thrown out rather than recycled. By reducing the need to use newspaper the product would help the environment.

The final product would be manufactured out of ABS through 3D printing or injection moulding for industrial manufacturing if possible.

Step 2: 2D/Inital 3D CAD Designs

I started by designing the project in Google Sketchup (just get Fusion360 it's better). When I was designing the project initially the design was a more rigid and sharp design that wouldn't keep a good resolution when I tried to export it as an STL which isn't as inbuilt function annoyingly.

After this, I decided to design the product in 2D CAD and to cut the design out of MDF sections. This allowed me to start producing a prototype. Which is the next step.

Step 3: MDF Prototype

  1. First I created the design a 2D cross section.
  2. These pieces were then cut out on the CNC Milling Machine to form a single piece of 600mm length.
  3. I then glued the pieces in sets of 3 with PVA using a piece of steel to line up the pieces and 3mm acrylic to ensure the opening didn’t close up.
  4. After these pieces dried I stacked them on while glueing onto a steel dowel.
  5. While they dried I produced a steel crank using the Brazing Forge & Hearth to heat the metal then I bent it using a hammer on the Anvil.
  6. Next, I filed the end of the handle into a dome to make it more comfortable for the user and safer.
  7. I then used glass paper to polish and smooth up the surface of the crank.
  8. Next, I drilled a hole into the metal after marking with engineers blue.
  9. I then designed and cut two end caps for the product on the CNC one with a hole and one with a rebate.
  10. Assembling the product I measured the length of metal and cut it appropriately.
  11. Next, I drilled the endcaps and screwed the product together.
  12. Last I used adhesive backed foam to attach a blind onto the metal rod to act as an effective blind mechanism

Step 4: Ergonomics and Anthropometrics

In early years education, it is important that the products and furniture in the classroom environment are designed with safety and ergonomics in mind. When designing for children or adults the anthropometric data such as arm reach can lead result in a wildly different products as such I have designed and considered anthropometrics which are shown and developed on this page.

Safety and Ease of Use:

Safety is a critical aspect of design which is amplified by the age of the end user. In my product I have considered the possible dangers such as the initial handle which extruded out of the product past the tables edge to far causing a hazard for people walking near it as well as problems such as sharp/pointed edges which can be solved through the development of the 3D model to include a filleted edge on most exposed faces.

In addition to the use of ergonomic design for safety, the product also uses ergonomics to help with comfort and ease of use for the design, such as with the designs splitting into three separate components to help with easy storage, assembly and use.

Anthropometrics:

Using the CHILDATA book developed by the Department of Trade and Industry I researched a range of information such as the hand size of children of both genders between 4 and 5 as well as arm reach data. From the book I found the diagram demonstrating the required measurement and then used the tables contained to extrapolate the required data.

The data shows that for children between the ages of 4 and 5, the hand size is between 6mm and 6.5mm. For my product, I plan on the design to be used by the teacher primarily with the option for children to use it if asked. As such the design is going to use the average adult measurements of 101.1mm to 116.2mm I’m going to use the lower end of the bracket to allow for the smaller handed children to use the product.

In addition, I also have researched the average arm reach of a sitting child (4-5) so the printed information such as handwriting guides are located in the correct place.

Ergonomics on my product:

In my product, the edges have been curved to help provide a more smooth and user-friendly product as well as improving the aesthetic. On the right are three possible handle design the Minimalist, the Gear and the Fisher. Which are where ergonomics have been considered most in my design. Using the average hand and finger sizes found using the anthropometric data book I designed the handles to fit the user as needed.

Step 5: Developmental Research: 3D Printing

With my project during prototype development I found that the product was difficult to line up and glue as it had to be made in a minimum of 12 cross section if using the CNC or minimum of 60 sections on the laser cutter. These sections are difficult to line up and glue as well as making the product difficult to finish.

As such using the departments 3D printer despite the long run time would yield the best finish for the project and allow for only 3 sections, this page covers the research into what materials and process work best.

Possible Materials:

In 3D printing, their is three main materials used Nylon, PLA and ABS. For my project due to the limitations of our 3D printer PLA and ABS are the only possible materials, as Nylon requires a different process entirely.

PLA (poly lactic acid) is a relatively new material and is the most common for home printing PLA is a biodegradable type of plastic that is manufactured out of plant-based resources such as corn starch or sugar cane. It allows for high detail 3D prints however this causes a rough surface on any prints.

ABS (Acrylonitrile Butadiene Styrene) is a very common thermo-plastic made out of crude oil. It is famously used for children's toys such as Lego and leads to people choosing ABS, because of its lifespan, its strength and its higher melting point as well as smooth finish closer to that of injection or rotational moulding.

Printing tests:

Due to a large amount of material and wanting to keep material costs low I decided to test non-official brands of the PLA filament. I had trouble getting the white PLA from sticking to the bed of the printer this said I did stick to itself during printing. With the green PLA, I had the opposite effect so I tried using green PLA to create a bed and then switch to white PLA. The results as shown below where less than impressive as the material separated layers mid print.

After researching into the use of ABS on our Makerbot Replicator Z18 the extruder on the 3D printer is capable of printing the ABS material. After talking to the manufacturer they said that the current extruder and 3D printer will print the material however without making expensive upgrades the results may not be of the high quality wanted. I decided to try the material regardless and while the feel and look of the material was better the layers deformed due to the lower temperature and resulted in a failed print.

Step 6: Developmental Research: Material

For my product the functions through the use of interchangeable rolls of a vinyl type material with custom designs printed on. This stage contains the developmental information and testing about finding this material.

Possible Materials:

For the rolls of material, I need a material that is strong, water resistant, can be printed onto and acts as a whiteboard. The main types of coated tablecloth which can collectively be described as 'wipe clean'. Are PVC tablecloth, Vinyl and Oilcloth, each with their own benefits and disadvantages.

PVC Cloth- Made entirely out of plastic they are generally cheaper than oilcloth or vinyl. PVC tablecloth doesn’t drape at the edges of your table as naturally as oilcloth or vinyl as it is stiffer and also creases more. PVC is very high quality, although it is slightly less hardwearing over a long period of time or with heavy use which may occur in a school environment. Mainly due to not having the cotton base that comes with oilcloth and vinyl however it does make the material thinner and easier to roll.

Oilcloth- An oilcloth tablecloth is generally very hard-wearing because it’s made from cotton with a PVC coating. As such the material also flows and bends/rolls better than the alternative materials.

Vinyl Sheet- A vinyl tablecloth is the same as an oilcloth tablecloth, however, Vinyl Sheets are similar to PVC cloth in that their is no backing, however, is very thin and flimsily.

Testing:

I performed a range of testing such as stain and sublimation tests the results of which you can see above. However decided to leave this out because it is a boring stage in the development. Overall I plan on using a 140mm long length of PVC Cloth as it has a good sublimation finish and keeps its waterproof coating. The material also rolls best and works well as a whiteboard. The material also has the benefit of being more aesthetically appealing when I asked other students and teachers they all choose the PVC cloth due to its look and being thinner than oilcloth.

Step 7: Developmental Research: Mechanisms

Despite the simple concept, my product requires a variety of mechanisms in order for the design to work. This step covers the mechanisms and designs for the storage; the material fixing to the end of the table; the retraction mechanism; and the screw mechanism to attach the product itself.

Storage Connections:

A critical part of my product is the ability the storage of the pens, paint or equipment that is needed for the lessons activity. The original 3D CAD and print solved this problem by including peg holes in the top of the product itself as seen on the right. Inspired by Lego to have modular items that can clip together

The problem with this solution was that the design had no way of locking the tray/pots put in meaning that the children to knock out or take the containers out when not meant to. After looking at a couple of designs involving physical locks or clips, the client suggested that having the storage slide in like draw trays would be good.

Working off of this idea I developed a dovetail shaped slider which allows for the modular components to be slid onto the product and are then more secure only coming out in one direction to the side.

The Retraction Mechanism:

As mentioned on the prototype development a vital aspect is the ability to set up and pack away children's crafts, interactive lessons or play activities quickly and with ease.

Ideally having the material being self-retracting would provide the best result and user experience. During the prototype development and analysis of a retracting blind, I found that a metal coil can be used to retract the material. Theoretically, I could manufacture a coil like this within school however it would be difficult and time-consuming and may not work.

As such I contacted a local sheet metal manufacturing company called KMF and arranged for the metal coils to be plasma cut out of mild sheet steel. They agreed to manufacture a coil however before ordering I felt that testing with Acrylic would be best and I found that the coil didn’t retract the material reliably or faster than hand cranking. So decided to look into gear trains connected to handles.

The concept of a gear the train is to convert the initial rotation of a large cog (the compound gear) into a higher rotational speed of the small cog (output gear). For my project this makes the material retract faster and more efficient for the teacher.

To design the system I started using an HTML gear generator on www.geargenerator.com which allowed me to design and test the gears.

From this site, I downloaded an SVG of the file, which I open in Inkscape, converted to a DXF and then sized appropriately in 2D design before exporting as the final DXF.

Once design I could cut the pieces out on the laser cutter and use wooden dowel to attach them to the MDF backboard and test them accordingly.

Step 8: The Fixing Mechanism

Table Attachment:

Since the very initial design the concept and napkin sketch the idea was to have the product clip onto the end of the product and use a G-clamp like mechanism to attach it to the product.

I decided to try making the screw mechanism directly into the 3D model and printing the screw thread and the screw itself. However, due to inaccuracy with the printer, it wasn’t reliable and caused cracking in the 3D printed part.

The final solution was to print the design with a hole which a metal collar made on the lathe could be inserted and then a metal threaded screw can tighten to the table.

Out of an aluminium rod, I machined a metal collar. The rod was taken down to the required size and then drilled out to form a 20mm cylinder of aluminium with an 8.5mm drilled hole through the middle.

The next step was to use a 10M tap to bore the threading into the metal collar. This results in the final collar which a 10mm threaded bolt screws into.

After finishing we the collar I made a threaded rod by using the manual tap and cutting lubricant to form a final rod.

I glued the collar into the MDF section using a 2 part epoxy after sanding the surface to ensure it adhered.

However when testing this rod to ensure it fit the imperfections of the collar combined with the imperfections of the rod meant that the design failed to screw in correctly.

Using a standard 10M bolt I shaped a rounded head using the lathe which would act the same as in a professional G-Clamp.

With the lathe, I followed the same techniques to manufacture a hollow cap with a thinner end which allows the cap to be crimped over the head of the screw and secure it in place.

After manufacturing the initial cap I manufactured a flat headed cap which had less impact on the table than the previous design.

Next, I 3D printed a handle which attached to the head of the bolt enabling easier use of the product.

Step 9: Fusion 360:

CAD Software

At the start of the year, I had no experience with 3D CAD. However I did have a good knowledge of Techsoft’s 2D design so was able to start experimenting with Google Sketchup at school and at home and I managed to make a simple design rather quickly however after a few months of learning how to design on Sketchup I learned that it couldn’t export to an STL format for 3D printing.

Due to this I starting learning and teaching myself Fusion360 a leading 3D design software with inbuilt rendering and 3D model handling for 3D printers. While it had some similarities and a lot of improvements I took me a few months to learn the software and become confident with it.

To make these designs I sketched a 2D cross section and extruded it to the required length. Then I used the sketch functions to build and cut out pieces off this extruded length. I then designed a 3D CAD of a table using the aesthetics and material tools to design the product's accessories, the table for use in pictures and the material sheet.

Step 10: Engineers Drawing.

Once again using Fusion360's drawing function I managed to create a high quality to scale engineers drawing which is required to get my qualification. It also helped in explaining parts of my ideas to a range of companies in order to discuss industrial pricing or 3D printing help.

Step 11: 3D Printing the Body

3D Printing The Body:

For my project the majority of the product is made out of PLA using CAD and CAM in the form of a 3D printer. At my school we have a Z18 Makerbot replicator which has a printing ability of 30cm by 30cm by 45cm. As my product has a length of 600mm I have had to split the main body up into 3 sections each 200mm long.

These sections have three 3mm diameter holes which go the full length of the middle section and leaving 10mm at each end of the two other pieces.

This allows for a 3mm diameter rod which can be glued with epoxy and helps to strengthen and align the pieces to form a single full length product.

When I first printed a 10cm length test piece the estimated time was 19 hours to print the design as such I started the print in the morning and allowed it to run overnight until the next day.

When I checked the design I found that the printing failed close to finishing during the last hour the filament resulted in a bird nest like print which as such meant the piece couldn’t be used.

Over the following few weeks I tried to print the larger pieces however they would fail before making any significant progress and as the design fails to function without the complete component.

During printing the main errors that occurred were failure for the raft that the design is printed onto to stick to the build plate. This then resulted in a failed overall print.

As well as having trouble printing my actual designs, other students at AS, A2 and GCSE all needed to use the 3D printer.

As such I contacted KMF a local sheet metal and fabrication company who have worked with me in the past. They agreed to work with me and to provide free 3D printer time if I supplied the files and filament.

I visited KMF and delivered the filament as well as explaining to the engineers my ideas and how I was planning on printing the parts. They agreed that splitting the design into three sections would provide the best print and work best overall.

After I had finished manufacturing the main body parts I used the schools 3D printer to print the modular accessories which hold the stationary and other components.

Step 12: The Material/Moving Mechanism

The mechanism:

I next step was the development of the metal crank handle. In each end of my design, I had left space for the fitting of a bearing.

The internal 10mm rod fitted between these and as such allows the material to extend and retract. The next step was the development of a removable crank. By adding a screw cap to the end of the crank and the end of the rod that extended out past the end of the body the handle could be screwed on and off appropriately.

The Material:

The material was then cut down using a paper template (see attached JPG) and a craft knife. I then attempted to sublimate the design for the product onto the PVC cloth however it overheated and destroyed the material. After reordering the material I tried a second time and succeeded in making the design work.

Step 13: The Finished Product:

After sanding and finishing the product with a soft touch spray the product was finished. Above are the final pictures of my product. I would love to make a range of more designs and make a lot of improvements, however, have got an exam to revise for.

Support the project:

*Please support my work and the project by voting for it in the in motion project.* By clicking the vote button at the top of this page. If I won any of the 3D hubs vouchers, I would love to spend them on getting the product printed to a higher quality out of ABS possibly.

Comments

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TheThinker (author)2017-05-06

Voting link is not working.

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RossB5 (author)TheThinker2017-05-07

Currently trying to sort the problem with instructables. Unfortuntely they feel the project doesnt involve 3D printing or motion so has been rejected.

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RossB5 (author)RossB52017-05-07

It has now been accepted and you are able to vote for it.

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Bio: I'm an A-level student from the England studying product design and doing a range of part time projects. I also have a laser cutter ... More »
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