Since sales are going good and the production schedule of the company is busy , a 3D printer is purchased for the research and development department of the company. With this 3D printer some test parts can be printed without needing the machining equipment.
The 3D printer that they use is the Stratasys Fortus MC 250, shown in figure 19. It is a FDM (layer by layer) printer that uses ABSplus themoplastics that is available in many different colours. This product-machine combination makes it possible to not only create prototypes,
but also to use this combination for production. This is the same 3D printer that will be used to create a visual representation of the final product. (Stratasys Ltd, 2016) The fact-sheet about the 3D printer and the ABSplus material can be found in appendix A.4.
4.4.3 SURFACE FINISH
After the desired shape is purchased by machining aluminum, the created parted should get a surface finish for the desired onlay and appearance. There are different types of surface finish.
PRE-TREATMENT
Before getting a surface finish on aluminum parts, the part needs a pre-treatment of cleaning and decreasing the surfaces. Also the natural oxidation layer should be removed by staining the part.
Through some surface finishes the structure of the aluminum is still visible. A desired structure can be obtained by: glazing, blasting and brushing. The appearance of these differently created structures can be seen in figure 20. (Aluminium coach, 2010)
ANODIZING
By a electrochemical treatment, an artificial oxidation layer is added to the part, when using anodization as a surface finish. After the
pre-treatment the part is rinsed, anodized, rinsed again and finally sealed.
This process can provide a clear surface finish where the colour of the aluminum is still visible. It is also possible to colour the part after anodizing and before sealing it. An example of a coloured anodized product is the apple IPod. (Aluminium Coach, 2010)
VARNISH TREATMENT AND POWDER COATING
Another surface finish of aluminum is a varnish treatment. These are multiple coloured layers adjusted to the aluminum. First a ground-layer of epoxy varnish is applied , whereafter the coloured layers are added through electrostatic spray painting. This can be done with liquid paint, or with a powder coating.
With power coatings, the powder is applied by electrostatic praying. Than the part is baked in an oven and the powder becomes liquid and covers the whole part. After baking the liquid particles will dry and turn into solid state again. The structure of the aluminum will not be visible after a couple of layers of varnish treatment. (Aluminium Coach, 2010)
WRAPPING FOIL
Besides all the surface treatments described for Aluminum, raping foil is also a surface finish option. This option allows every possible appearance needed.
The wrapping foil is adherent and available in many different appearances. A couple of examples can be seen in figure 21. When applying the wrapping foil, the protective foil is removed from the adherent side of the foil , whereafter it is placed on the part. Recovering mistakes or difficult areas can be wrapped by heating the foil over the desired area. (wrapfolie.nl, 2016)
All these options for the surface finish of the product will be taken into account when designing the final appearance of the product.
4.4.4 ASSEMBLY/MAINTENANCE
Besides design for manufacturing, design for assembly is also a design strategy that could be useful to use when designing the McArm. Design for assembly aims at the reduction of parts. Reducing the number of parts, makes production, assembly and logistics much easier.There are three main question to ask, when determining if a part can be excluded. First question: Should the part move relatively to an other part? Second question: Should the part be made out of a different material? Third question: Should the part be releasable relatively to other parts for assembling or maintaining the product?
If the answer to all these questions is ‘no’, than it should be reconsidered if the part could be integrated with one or multiple other
parts of the product. Besides the number of parts, standardization is also an important aspect of design for assembly. For the standardization of a product, it is necessary to keep in mind that a larger number of simple parts is easier and cheaper than a lower number of complex parts, in most cases. This is especially the case for small series production, as is the case for Focal Meditech. (Kals et al, 2012)
When the product is in use, all kinds of problems can occur.
With the mechanics all covered up as desired according the previous sections of this report, is needed to be able to reach the inner parts.
Reduction and standardization of the parts, along with the reachability of the inner parts will be taken into account in the detailing and evaluation of the design.
Figure 19: Stratasys Fortus MC 250 (Stratasys Ltd, 2016)
4.4.5 REQUIREMENTS
During the production analysis some requirements and guidelines came up. Below all these requirements and guidelines are summed up:
-Product contains as few parts as possible -Assembling product parts is as standardized as possible.
-Product can be obtained by using Focal Meditech’s currently available production methods
-Product is producible according to the guidelines presented in appendix A.3
-Product contains only the minimum number of required parts
-Standardization of the product is kept in mind when designing the product
-Product parts are easily releasable so rapid maintenance is possible
Figure 20: Pre-treatments of aluminium: blasted, glazed, brushed ( from left to right) (alumnium coach, 2010)
4.5 Requirments
All requirements and guidelines conducted in the previous sections are collected and organized according the desired product value that they contribute to. The values used for this categorization
are: functionality/usability. producability, acceptability and other.
Besides this categorization, all listed requirements and guidelines are linked to each other and divided into requirements/ characteristic and specification that suit with these requirements and characteristics.
Within the scope of this assignment, the requirements and characteristics that belong the acceptability value are the most important requirements and are shown in table 22 on the next page. All requirements can be found in appendix A.5.
Acceptability Product does not create stigma Product creates possitive reaction from
bystanders Desirede associations: Empowermenet, Strengt, Friendlyness, dynamical Product is appealing to the majority of the users Product resembles mainstream products
Main shape does not contain very contrasting thicknesses
Circular shapes are repetetively present on the product
Product is simple
Detailling of the product is determined by material choices
Product is not associated with medical products Product is not white Product matches user’s personality and lifestyle Product personalizable
Product is fully finished No screws and other assembling parts visible Construction is not unintended visibile Product is not inconspicious Product is not hided
Product is not unchoicenly striking Product matches the colouring of the
wheelchair(mostly black)
VALUE REQUIREMENTS/CHARACTERISTICS SPECIFICATION
4.6 Conclusion of the Analysis
In this phase the problem, stakeholders, competition, context and production is analyzed with relevancy to the assignment. From all these analyses a personal design vision for defining the appearance of the McArm is arised. in the coordinate system below the desired shift on the function/design and notability scale is shown.
The design of the McArm will be a design that is not hided, but unnotable. Notability of the product can be personally added by choice. This will be done for a product that still has all the required functionning, but with enough
attention for the design of the product. All analyses done for this phase are transformed into requirements and guidelines that should provide a product that fits the set vision. The set of requirements can be found in appendix A.5