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Joseph Oberholtzer is a tinkerer and a Mechanical Engineering Student at the Pennsylvania State University. Visit [1] to see some of my projects.


The evolution of the OHM - April 20, 2013

After having my fair share of experience printing, troubleshooting, and building RepRap 3D printers, here are my thoughts on improvements. RepRap has evolved over time to meet the needs of its users. The builds are a good mix of basic components such as threaded rod, nuts, and bolts , as well as simple to print components. Although RepRap and our build the Open Hybrid Mendel (OHM)[2] is a blend of software, electronic, and mechanical systems I will keep my suggestions to the mechanics.

The OHM support structure is built primarily of threaded rod nuts and prints. The design results in a simple build but one that requires significant tuning and retuning specific to each printer. The need for tuning allows the use of very imperfect parts which is definitely an advantage. Design goals for improvements to the structure should be the use of imperfect parts but reduction of standardized tuning.

The area that i think could use the greatest improvement is the extruder. The extruder uses many printed parts to handle high temperatures and high forces. PLA’s structural properties quickly degrade with increased heat so extruders tend to warp and have a short service life. An all metal design [3] with a geared stepper motor [4] could provide significant increase in durability and precision. If I were to invest a lot of time into a RepRap redesign I would definitely focus on the extruder

Recycling and Dual Extrusion - April 17, 2013

With the RepRap design well established many people are choosing to look into ways of expanding RepRap functionality. The two projects I will focus on are the filament recycler and Dual Extruder.

The purpose of the recycler is to take old plastic and convert it back into a printable form. The idea has generated a lot of discussion [5]. There is also a recycler (Filabot) that will soon be available to the public[6][7]. The trick is that many plastics outgas when they are heated. If you melt down ABS plastic you will need to add acetone to bring it back to a printable form. Even if the cost per print would decrease drastically by grinding up old ABS you now have an additional process and consumable in 3D printing. This added complexity results in no significant gain; any money saved [8] will be negligible when you factor in initial investment and the frustration of another build.

The project for a dual extruder is where my interests lie. While many people only think of using a dual extruder for multiple colors, I would like to emulate industrial FDM machines[9] that use a second extruder to print a support material[10]. The support material can then be dissolved into a base solution. So why don’t we have dual extruders? Well although some say it is a chicken or egg game because won’t be build till the software does and vise versa[11]. The reality is that the extruder [12] [13] and necessary electronics [14] already exist. Commonly people are making custom modifications to the printing firmware[15] but there is little software that claims dual extruder capable [16][17]

Looking Back on my RepRap Education - April 15, 2013

The RepRap course has been a great opportunity to become acclimated to an industry that many hold as a revolution. The many areas that 3D printing has been applied and the many avenues by which 3d printers are designed were unknown to me before this course.

Much emphasis was placed on the open source movement and projects that our peers are working on. We only lightly touched on industrial capabilities and applications of 3D printing. While industry isn't as easily related to, the capabilities and techniques used are worth exploring. Knowledge of what works and doesn’t, in any aspect of 3d printing, can help in improving our own designs.

Another area of interest is modifying existing technologies into 3d printers. While RepRap has been designed well for its purposes, I found a lot of time is lost to building tweaking and improving the RepRap's physical structure and degrees of motion. The challenge of automated movement in a rectangular coordinate system is not a new one. Milling machines offer affordable, high precision, high rigidity, movement [18]. This mill ([19] $1300) can be converted into a CNC [20] and it isn’t a stretch to imagine a FDM extruder[21] fitted to the end of the CNC. The financial investment is more significant than a RepRap but when you compare capabilities with Replicator 2[22]($2200) or a Haas CNC[23]($50,000) the prospect is tempting.

As for the evolution of the course, when the course had few printers it made sense to have every student printing and working one all the printers. I imagine it wouldn’t be difficult to keep track of the quirks of each printer. However the course is growing and will soon have more printers than students. It is very frustrating to work hard troubleshooting your printer and making it print well only to return the next day to a printer that doesn’t print and have no idea what was changed by the last user. Even the instructor says he can’t keep track of the printer's status. I suggest access to the printers be limited in the future.

I suggest that groups of 3 teams (9 or so people) have exclusive rights to their printers. This group structure would foster community and allow easy communication about changes to printers. Access to limited printers will encourage responsibility, because if your printers are down you must fix them or you can’t print. This will eliminate the frustration of printer fairies wreaking havoc every night and having no clue what was changed.

Write a better blog! - April 6, 2013

Two weeks ago our class reviewed blogs 4 and 6 of our teammates. The blogs of Mark, Carina, Matt, and Chris received regular well deserved praise. Common threads in the successful blogs are the use of multimedia, outside links, tables, and clear organization. The blogs are well written but my work could most benefit by emulating the enriching features listed [24]. One area that I think I do well is giving a relevant title and a date to my blog posts. Shout out to DM0lition21[25] for choosing my blog 6.

Digitizing our Physical World - March 27, 2013

Laser & Photo Generated Models

Autodesk, producer of industry leading 3D modeling software used in engineering and movies, has been aggressively pursuing the consumer market in recent years. As a student I have the benefit of free access to most of the Autodesk products[26]. For most people this software would cost tens of thousands of dollars and a huge learning curve. Autodesk recently announced its latest software, ReCap [27], which will help to eliminate this technology gap. ReCap is an application that can take laser scans or high quality photographs of a physical object and turn them into a 3D model. A TED talk[28] was given on a similar software and shows how photometry works. ReCap is very user friendly and fully integrated into Autodesk's existing 3D modeling programs. A video shows simple manipulation of the 3D scan and the ease with which virtual models can be included[29].

Autodesk claims that the software will be available for free on thier app market but as of writing this the app is not listed[30]. If you cant wait to try the technology you can use ReCap's predecessor 123D[31].

Look at the blogs of my peers - March 22, 2013

This week I will be looking back at some of the blogs of my peers[32] in the Penn State RepRap course. Replying the the given prompts every week, the group has produced a significant body of work regarding current events in RepRap there are blogs that stand out. These noteworthy blogs deserve deserve additional XP for the reasons given below.

For blog 6 on the rapid growth and integration of additive manufacturing in society:

Mark Keller[33] did a good job in the replying to the given prompts as well presented additional research and analysis of the issues. His use of images also improves the aesthetics of the blog.

Alex Punzi[34] provided a well organized and clearly articulated perspective on the topic. Alex also included valid reasoning for the limitations that RepRap faces if it were to be used as a classroom tool.

David Long [35] wrote a strong review and provided noteworthy research into the topic.

For blog 4 on a hand prosthesis made from a 3D printer:

Xiaomo Zhang[36] referenced past blogs outside information and directed the reader to a page where you can donate to the cause.

Chris Marcocci[37] touched on similar projects and applicable technologies, as well as providing a overview of the pros and cons of open source vs closed source.

Carina’s [38] post was brief but no less informative as images and tables were used effectively. Additional links were also provided.

Crowdsourcing with Kickstarter - March 6, 2013

A critical issue that faces anyone that wants to start is small business is financing. All business must be supported through the initial stages until the day that it can support itself. When my parents decided to start a flower nursery they followed the route used by many small business owners. They scraped together their savings and received loans from family members that believed in the business. Even after the business was started, they worked other jobs to bring more into the company. This method of financing is referred to boot strapping.

If my parents not only tapped into the family members that believed in their business, but had a way to draw on the community members that supported a nursery then the business may have been become profitable much sooner. This method of financing is called crowd sourcing and websites like [39] are built around the idea. In return for the donations a return gift or product is offered.

3D printing fits well into the kickstarter model. Most 3D printers use kickstarter as a means for early adapters to place orders. While some projects have sunk others have received upwards of 1000% of their requested funds.

  • The Tangibot [40] attempted to manufacture Makerbot's highly successful Replicator 2 [41] at a lower cost. The Tangibot did not succeed, possibly due to the high donation goal and the project presentation as a cheap knock off of a highly respected company.
  • The Robo 3D printer [42] is a printer invented by 3 college students from San Diego, CA. The product looks like an optimized and prettied up version of an open source printer. The team raised $650,000 on kickstarter, 1300% of their $49,000 goal.
  • The Printxel 3D Printer [43] was entering beta testing and received 1600% of its $7500 goal.

Other projects are bringing generating an unbelievable amount of attention.

  • The 3Doodler [44] is a 3D printing pen that has gone viral. The kickstarter page has 19 days left and has generated $2,061,300, 6900% of their $30,000 goal. This is the first low cost 3D printing solution that does not have intimidating robotics or require the knowledge in computer based 3D modeling. This product opens 3D printing up to many new areas such as art, quickly commutating design concepts, and children.
  • Form labs, a company started out of MIT, like many others is attempting to bring quality low cost printing to the consumer market. Their approach is to build a printer using technology from recently expired patents in Stereo Lithography, a type of 3D printing. Form Labs gained such attention that their kickstarter[45] received $2.9 Million pledged of the $100,000 goal. The huge success did not go unnoticed as 3D Systems is suing both Form Labs and Kickstarter for infringing on a patent that has not expired [46]. The suit is road blocking form labs and has brought attention to the many other patents that slowing down progress in 3D printing.

If you want to see more 3D printing kickstarters check out:

  • The B9Creator [47] uses similar technology to the Form Labs printer and received 1000% of their donation goal[48].
  • The Filabot [49] is designed recycle plastic that would normally be thrown away, like a milk jug, and turn it into plastic that can be used in a 3D printer. The project received 300% of its goal [50].
  • Printrbot is a bare bones 3D printer with a very small footprint. The kickstarter community liked it so much it received 3300% of the requested budget[51].

Kickstarter has become the mecca of crowd sourcing, providing resources to thousands of entrepreneurs, artists and celebrities. The model developed by Kickstarter has many advantages and similar services are already popping up [52]. The future of crowd sourcing will undoubtedly be heavily influenced by the success and failures of Kickstarter.

But isn’t kickstarter a benevolent entity that brings people together to support of a common cause? In many ways yes, but as explained by The Baffeler[53], as a for profit entity Kickstarter is getting a significant portion of all donations. After the slice for kickstarter comes taxes, preparing rewards, and many other monetary and nonmonetary costs. Hopefully in the future there will be a utility that is to kickstarter as craigslist was to eBay. It won’t be a replacement but it will better align itself with the spirit of crowd sourcing.

In financing a project, crowd sourcing through Kickstarter that has the advantages of a huge community to pull from and a clean professional way of getting your message out. Of course the option of bootstrapping and a traditional store front isn’t out of the question. With this traditional route you are able to develop a strong community that can remain connected to you. You also don’t have a middle man taking a cut and a list of obligations to fulfill.

3D Printing in Manufacturing and Education - February 23, 2013

A recent article by the New York Times [54] comments on the rapid development of 3D printing and the impact that 3D printing on manufacturing and education. The development of 3D printing is progressing so rapidly that It is difficult to predict more than a few years out. In 2010, researchers at the University of Southern California predicted that 3D printers would not be able to build a home for another decade. Just last week Softkill designs announced its intention to print a house later this year. In education, the University of Virginia believes that 3D printing will be integrated into every school in America. They are leading this change by working with Charlottesville K-12 to integrate printers into the classroom.

The progress of 3D printing is being looked at by some as a solution to the United States’ waning manufacturing ability. Earlier this month in the State of the Union address, president Obama spoke of the potential for 3D printing in manufacturing and steps he is taking to further the abilities of 3D printing in manufacturing. The recognition of 3D printing’s potential from the nations president is sure help by peaking the interest of wealthy companies and businesses. However solar power and hydrogen powered cars show limited effectiveness of the government’s direct push for technology.

In an article by the Universit of Virginia (UVA) [55] details are given on the way 3D printing is being used in undergraduate engineering courses. Any engineering analysis requires assumptions and the ability to break down the problem into smaller parts. The intuition necessary for this analysis is developed over the course of an engineering education. UVA is helping students to develop this ability by letting students print 3D models of the systems they are working on. The printers used are able to print a functioning dynamic model without the need for assembly. This system should work well for early engineering courses so long as the intuition can be cultivated. Later courses such as fluid dynamics and heat transfer will not have the luxury of physical models.

Although UVA used commercial 3D printers, RapRap printers could be used in classes in much of the same way. The most significant difference is that most RepRap printers are not able to print support material and therefore could not print functioning models. RepRap models could be printed as separate parts then assembled. With the unpredictably quick pace of 3D printing development the only thing to be sure of is that people and industries will continue applying 3D printing to solve more problems.

Printing Stolen Goods - February 16, 2013

The abilities provided through 3D printing are amazing. It is the ability to turn raw material into an unlimited number of objects. With the question of what can and can't be fabricated is fading into the background the question of what should and shouldn't be fabricated is receiving renewed attention. An article by Michael Weinberg titled "Whats the deal with copyright and 3D printing?"[56] examines the intellectual property issues related to 3D printing, primarily copyrights. The first half explains the systems used in the USA designed to protect intellectual property. And the unclear lines that the courts must draw to protect art with a copyright but avoid protecting anything useful with a copyright. When a design is both useful and artistic the court must determine the separability of the art and utility. Through examination of several cases the author concluded rules to find severability:

   1) Determine if artistic elements play a primary or secondary role in the object. 
   2) Look to see if any potentially severable elements were driven by utilitarian needs.
   3) Determine if there are creative elements that were designed without regard for functional requirements. 
   4) Determine if independent, artistic judgment drove the creation of the non-functional elements.

Rule number 4 is regarded as the most widely applicable.

Following the issue of severability the article addresses what art is considered copyrightable. In many cases the 3D scan of a piece of art is not copyrightable. A Computer Aided Design(CAD) model is copyrightable but only in the areas where the design goes beyond the utility. Once again bringing up severability.

As a student Mechanical Engineer and an avid tinkerer I found this article useful in understanding shaping of the legal system that I will be practicing in for most of my life. Looking at the transitions of music and movies into the digital relm. I hope that transition of physical property will be able embrace the advantages of digital copying as Netflix and iTunes were able to for their mediums.

Open Sourcing Human Needs - February 8, 2013

An article by Sean Gallagher at Ars Technica [57] gives the account of tinkerers Ivan Owen of Bellingham, Washington and Richard Van As of South Africa who recently published the their design for a robotic prosthetic hand [58]. The dynamic duo got their start in an effort to make prosthesis fingers for Vans As who is missing fingers on his right hand. They started out by shipping prototypes back and fourth but with a donation of a 3D printer for each of them from Makerbot, the design process improved dramatically. In a mater of 3 days the duo was able to come develop a prototype hand for Liam, a South African boy that lost the fingers on his right hand to Amniotic Band Syndrome[59].

Not only is 3D printing giving back the utility of a lost appendage but at TEDxCambridge Industrial designer Scott Summit presented his work in giving ownership, personality and uniqueness back to lag amputees.[60] Tattoos, lace, even chrome are inspiring these one of a kind legs.

Applications of Additive Manufacturing - February 1, 2013

Construction of Shelter

In a TEDx presentation [61] Behrokh Khoshnevis presents the use of additive technologies in residential and commercial construction. The concept is essentially to upscale a Rep Rap printer and hang it from a gantry. Aside from 'printing' concrete the device can place structural materials, plumbing, and electrical components. Khoshnevis is not alone on his quest, researchers at The Loughborough University have printed a 2 square meter park bench [62].

The perfect steak, heart and kidney

The medical field has developed the ability to use living tissue cells as a printing medium. If researchers are successful, skin will be printed directly onto wounds, replacement organs will be printed, and you may even have the perfect juicy printed steak for dinner [63]. RepRap is specifically having an impact. Researchers at U Penn are using RepRap to print sugar networks which are used as nutrient pathways in large tissue samples. Although printing cells is on the cutting edge of medical research, it didn't stop a hackerspace from designing their own do-it-yourself bio printer [64] and giving the plans away [65]. Even if it is one of the more difficult printers to build, all that hard work will let you join in on the bio medical fun.

If you thought your printed steak was pretty good there are burritos[66], custom chocolate treats[67], cookies with icing [68] and a $300K hamburger [69] where that came from.


The needles and thread are being replaced by strings of code. Fashion designer and futurist Iris van Herpen is responsible for the transition[70] and while needle and thread wont be fading from vocabulary any time soon, the printed clothing may be here to stay. Not only is 3D printing becoming a part of the fashion world but it is influencing Continuum Fashion to model some of their needle-and-thread work after 3D printing. While Herpen is making a new gown, another Dutchman, Dirk Vander Kooij is recycling refrigerators into highly awarded (and priced) furniture[71].

Mother of all Demos - January 25, 2013

The “Mother of all Demos” [72]

The video shows the beginning of the modern computer in 1968 with word processing and the first mouse. Without knowing more about the other technology of the era it is difficult to appreciate this step in technology. For some perspective, Microsoft and Apple were only founded in 1975 and 1976 respectively. The most impressive aspect is that the user did not need to know any programming to operate the computer. The new market that these computers could reach with their reduced learning curve would be obvious.

In a speech by Professor Richard Doyle at Penn State University[73], he addresses the revolution in computers that the "Mother of all Demos" represents. At the time of the presentation, people thought the demo was a hoax. Although the US government copied his prototype they were unable to make it function properly because they lacked the open and creative culture that Stanford had and had collaborated to make the prototype a reality. Doyle goes on to illustrate the power of collaboration that an open flow of knowledge allows. Modern science got its start with the Royal Society which cultivated the open sharing of their knowledge. The growing momentum of the open source movement is cultivating a similar idea, the idea that not only should knowledge be shared but it should also not be the property of an individual. This community has grown in many areas of technology and has an astounding ability for creativity and education.

The real question is what will happen if the open source community continues to expand. Can open source become more capable than it's commercial competitors? The competition is an unfair one as companies will always be able to build off of the open source community but they can keep their own secrets. Open source is free by definition so the community may only need to offer acceptable alternatives to costly commercial solutions. No matter the result the open source community will continue to grow collaboration in a way never before possible and all of humanity will come to benefit.

5 Things of the Thingiverse - January 18, 2013

1) Open Source Robotic Arm / thing:387 This robotic arm will allow manipulation of many objects and although the design does not include an STL file, the files included for the plexiglass parts could be condensed to reduce part count and printed on rep-rap [74]

2) Nautilus Gears / thing:27233 This 'thing' is beautiful from both an aesthetic and design stand point. Printing the project is simple with only 3 part files. [75]

3) Asteroid Vesta - hi res from NASA model / thing:42888 Its a big lump of of 3D printing. Useless. [76]

4)Inverse Colbert / thing:9196 Colbert Bust with a Picasso twist [77]

5)Scary Animal / thing:35897 Cute kind of scary [78]

Tinkering in America - January 18, 2013

At a very early age I remember my brothers and I hunting for old electronics around the house just to smash them into pieces. While smashing an old VCR(there all old now), I came to the realization that every little electrical and mechanical part was there for a reason. Not only that, but a person had decided on the design and propose for every part. I think that was the day I became I tinkerer. Equipped with an engineering education and tinkering friends from many backgrounds including engineering, art, chemistry, and math.My ambitions and projects have grown and some of my projects are documented at [79].

An article on [80] illustrates the differences between the corporate design methods and the methods of tinkerers. Corporate design is driven by the bottom line and as a result does well to enforce the idea that their product is a magical black bock that once broken must either be fixed but them or preferably thrown away and replaced. The author uses the example of how Steve Jobs and Steve Wozniak started apple through tinkering with what they had around them. The irony is that currently apple products are the worst offenders this corporate culture. A user can not even replace an iphone's battery without special tooling to brake into the phone. In all fairness this design approach has likely been a result of trying to reach a wider audience by making the design more streamlined and intuitive to the user.

At the end of the article is the line, "...preserving the habitat of the tinkerer is one of the few time-proven ways we as a nation can get back on track." This idea has been proven over and over again as the most successful companies (Microsoft, Apple, Facebook, etc.) were all created by tinkerers.

Lastly, in an interview with Charlie Rose[81], David Kelley gives perspective on what makes his design firm so widely successful. The principals of diversity on the design team and empathy for the end user are iterated repeatedly in the interview. Kelly is a strong believer that every person is creative and the power of self-efficacy. Having a divers group of people on a design team is rare, however it doesn't need to be. I find that almost anyone that I talk to about a design will immediately have ideas on how it could be improved or uses for the design that I never thought of.

At the end of the interview Kelly shows the 3D printer that he is building with his daughter. 3D printing seems like the perfect tool for a design environment that encourages quick prototypes and many iterations of a design. As the Rep-Rap community at Penn State grow it will hopefully pull in a more divers group of people that will offer new perspectives on what the future of Rep-Rap can become. Penn State already does an excellent job of iterative design with a whole new generation of Rep-Raps being build and tweaked every semester. Here is a video [82] of the IDEO design process in action.