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The Elephant pen – Part 1

18 September 2015

Hello, I’m Jonas, one of the younger passionate members of the CONID team.

Usually my work is done behind the scenes, unnoticed and indirect. I don’t assemble Bulkfillers, I make the production drawings. Maintaining the catalog and updating this blog is also part of my input for CONID.

Until today, where I would like to share an insight on my recent and interesting project: the Elephant pen.

A while ago, CONID got hands-on a brand new Tripod Maker 3D printer. Worth saying is that our choice to get specifically this printer was determined by the fact that it’s also made in Antwerp. After a long period of testing and seeking out the capabilities of this nice machinery, I got used to it very well. To keep interests up to level after knowing what could be printed and what not, a new challenge was needed…

 

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As much as the Giraffe started out as a sales joke, the story of the Elephant pen isn’t much different. If I remember well, the idea grew out of a conversation with Werner, where he mentioned that he wanted to see me print a Bulkfiller. Knowing that the precision to print such small parts could not be reached with this type of printer, I had to disappoint him with the negative answer: “It cannot be done without compromising the pen’s geometry. Unless I would scale it up, but what’s the point in that? Who needs a huge pen?”

With a grin on his face, and a slight pause, he added: “an elephant perhaps!”

A new – and very time consuming – project was born.

Both Werner and I have the tendency to feel attracted to doing things that others would describe as “not done”. This means that the scale of our project unmentionable needs to follow this desire. How big do we have to go to be “not done” ? The agreement was settled within a couple of minutes: 10 to 1 would be a nicely exaggerated and challenging ratio. This would result in having a Regular Flat Top Bulkfiller with a total capped length of 1m36. For the imperial readers among us: 4.46 ft.

THE PRINT-JOB: Preparation

With the available print volume being the size of a small bucket, all large parts like the cap, clip and barrel needed to be sliced into smaller and stackable pieces. Since all of our 2D production drawings are being generated out of 3D Cad software, the computer model was already present. So there I went, focusing on each part and defining where to chop it. From there on, sending a checked and double checked 3D drawing to the printer and initiating a print is a piece of cake. But where is the challenge if all went so smooth? Well…. It didn’t.

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Being an impatient and over-curious person, one of the first things I wanted to see coming out of the printer was the nib. This one was just small enough to send to the printer as a whole, no slicing needed. The predicted time to print it exceeded 15 hours, and although I started it on a Friday, when I woke up early the day after without much sleep, I had the inevitable urge to hop on my bike and head back to CONID to have a provisional glimpse of the slow printing progress. In the meanwhile being familiar with complex print jobs going terribly wrong, I knew there was quite a high chance of failure. But only god knew what I could expect.

To my utmost surprise, when entering the ‘prototype lab’ I was able to admire the astonishing beauty of technology. Against all expectations the print head was still nervously dancing above the almost finished size 60 ( #6 x 10 ) nib. Hearing nothing but the harmonious humming and beeping of the printer motors was the encouraging satisfaction that was needed.

At a quarter past 6 AM, after being present in the lab for a few minutes, it seemed as if another invisible guest entered the room. I believe he listened to the name Murphy and is known by his famous law. Simultaneously with a short crunchy noise, sounding like a slice of toast breaking, I witnessed how the precious nib detached from the base, and started wiggling underneath the unconscious and steadfast print head. Although this irrevocably meant that this print is ruined and almost a day of indispensable time got lost, I could do nothing else than keep gazing at the almost hypnotizing view of an up scaled plastic nib being wobbled around by a strange looking and overly busy machine. A grin appeared on my face. I was not turned down, nor disappointed. I was glad that this challenge was real.

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DEBUGGING THE NIB

It quickly struck my mind that the flaw was caused by being overly enthusiastic. Such a slender and high piece definitely needed supports. Even with no basic knowledge about 3D printing, one could easily confirm this theory by common sense. After adapting the model, and manually drawing the supports that will be printed as well, I gave the nib another run. The day after, two steps back were made instead of achieving the prolonged progress. Least can be said that my experiment did result in a fancy piece of artwork. More changes were conducted, alternate methods were applied, but again: I failed in achieving a printed nib. Time to put that ungrateful geometric nightmare to a rest, and move on to something easier. Some O-rings might suit my mood a little more.

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THE START OF A LONG JOURNEY

Perhaps it’s time to explain in short how the actual printing takes place. The material used is a plastic filament, stored on a large reel. While printing, this filament gets transported through a tube to arrive at the print-head, where it’s squeezed through the heated nozzle, which temporarily softens and melts the plastic. The print-head than moves to the positions where material should be ejected, and builds up the parts in thin layers, from bottom to top. Since this process takes place in space, each new layer should have sufficient amount of support by the previous layer. Otherwise gravity will make sure the ejected molten plastic falls down and creates thin hair-like strands which will quickly turn your print into a not so delightful spaghetti. Defining the orientation and the slicing of the parts is crucial to respect this perk.

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Therefore, my O-rings are printed in two halves, and fused together afterwards. Just two similar pieces with a nice flat surface for gluing it back-to-back. Compared to the feed, it’s child play. Due to the numerous buffer grooves which will conclusively collapse as pancakes when printing the feed in vertical orientation, I had to slice the model behind each buffer groove. The result is a puzzle of at least 41 separate parts. In the picture below you see 31 of them, laid out consecutively and waiting to become part of the most crucial and glue-consuming feature of the Elephant pen.

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The resolution of the Tripod Maker is excellent, but not unnoticeable. It translates in small steps, ribs, dimples and bulges. So the next thing to do when a part is printed, is making sure that all surfaces get smoothened and seam-free. For this, I have used a polyester repair kit and sanding paper. For those places where the seams are too narrow for the paste-like polyester, but too wide to get filled up with primer paint, I used some enamel paint which nicely penetrates and fills the smallest imperfections. After at least a day of drying, this can be easily sanded down and smoothened.

 

Personally I gain most satisfaction when spray painting this primer coats. Transforming the dark colored polyester-plastic hybrids to neat homogenous substitutes, veiled in a matt snow white coating, is really pleasing to the eye. For the first time the geometry gets fully appreciated, and the effort of sanding down rewards in a surface that lacks any glitch or defect. At least, that’s the way it should be. Because often these unwanted deformations only get visible after the first coat of primer. Nothing is lost when this occurs. Every coarse spot, every tiny pinhole, every particle of dust that got caught in the drying surface, is a motivation to choose a fresh piece of sanding paper with fairly smaller grit, and carry on with the amusing and peaceful post printing process.

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If all goes well, I will not let you wait too long for Part 2 of the Elephant story.

 

Jonas Haertjens

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1 Comment

  • Reply Francis Goossens 18 September 2015 at 20:54

    Dear Jonas,
    I’m completely overwhelmed seeing the fantastic challenge you took on, my sincere congratulations !
    C’ant wait to see the finished “elephant” Bulkfiller, please keep us posted on the further evolutions !
    Kind regards, Francis

  • Leave a Reply to Francis Goossens Cancel Reply