last update: 13/01/2018 - nitriding, patent & licence...
A great collective energy binds experienced manufacturers, apprentices and people passionate about sound sculptures. Each in their own way participate in building a community.
The most valuable advise we received from one of our elders was "You have to work in a team !" and this energy has helped our Shellopan project to persist since 2010.
Shellopan is a cooperative enterprise, and is actively exploring an alternative way of exchange than what we have grown used to in our market economies. Following the message of our elders, we decided to open our workshop and share our means of production* in the manner of a fablab dedicated to the sound sculpture.
(* here is one of our biggest means of production : our tool to make deep drawn handpan shells)
1) our business approach
In trade, the secret of a recipe or a process maintain the scarcity and increase profit. The recipe -when it is not secret- is a patent or a license which also participates in making profit. In this way, knowledge becomes a market value.
Our work has been possible thanks to the work of our precursors and information they have published or communicated with the desire to see the shared knowledge becoming more important. Our approach is to honor them and try to in turn share our knowledge and experience. To further collective knowledge, it's important that the people that use what we provide adopt the same sharing approach.
We therefore choose to focus our "fablab" activities more on those looking to get involved that have a sharing approach in balance with their business. If services and prices are listed here, we have no will for commercial development or inducement to consumption. The services are offered through a voluntary process of sharing and they will be accessible only after prior agreement and/or by appointment. As should be for everyone on this earth, we have the freedom to choose when and to whom we devote our energy.
Even if we do not find it appropriate, we respect the traditional forms of business and we hope to receive the same respect when we choose not to participate.
2) characteristics of the Shellopan deep drawn Handpan shells
Information regarding the availability and the quality of the Shellopan handpan shells : we are launching a production every time we find the good steel of our choice, it can take several months. We always keep a stock for the fablab activity and a stock from each batch for search and development. These considerations are given priority over resale activity of our shells. We have no commercial development objective of this activity and packing shell to send them by carrier is not our passion.
The steel reference "DC04" is well known in our community since PANArt published information about this steel. Only this reference is not a warranty of good steel because this norm has way too wide tolerance range. It's really easy to get a bad DC04 batch (eg : DC04 with DC05 or DC06 parameters). Of course "good" or "bad" steel are personal appreciations, but good parameters for deep drawing industries are not good for our compressive stresses managment, so we need to find a good balance when we choose a new steel batch. We are thinking that it's a non sense to buy steel or shells without the chemical and physical caracteristics of the steel, those information are really usefull for progressing. It's impossible to buy two time the same steel, or you need to buy 25 tons (>6000 shells).
Different methods of forming shells
(in increasing order of personal preference, benefits and defects in brackets):
- manual hammering pneumatic sand rammer (+ cheap / + can control the thickness with experience / - risk to health, dangerous for the muscles and joints)
- manual spinning or CNC (+ cheap / + ease of forming the port on the bottom shell / - problem of inconsistent thickness, sheet metal is refined further away from the center)
- hydroforming (+ easy choice of the depth of the shell - unable to control the thickness distribution, the final shell is thinner at the center up to 25%, we have eliminated this technique for this reason)
- spinning inside rings (see Pantheon Steel process, + possible control of the thickness according tooling / - need a thicker sheet initially as spinning will only refine the material / - marked grooves in the surface)
- Stamping / Deep drawing on hydraulic press (+ control the thickness of the sheet with the possibility of letting go material from the blank holder, - expensive tooling and need a huge press)
Shellopan shells are deep drawn under a 400Tons hydraulic press with a tool that we have co-built with a french industrial prototyping company.
Dimensions and thickness information
size: external 550mm, internal 530mm, high 130mm - starting thickness 1mm
A very important feature is the distribution of thickness after stamping (see photo below). The slippage marks are the consequence of the method we use to control the thickness repartition: steel is coming from the ring to avoid to stretch too much the steel inside the shell. The only way to be able to know the thickness distribution is to be able to mesure it with the good tools (ultrasonic sensor or other tools).
Information about the "raw" steel: the steel that we use has a light corrosion protection applied by the steel manufacturer in the form of a thin layer of oil. Stamping work, laser cutting and the various manipulations needed systematically alter the quality of the surface and more or less visible traces of oxidation can form during transport and storage. Sanding the shells may be requested just before packaging / transportation but this will make them more sensitive to rust, this choice is advisable for those who provide the transport themselves and have a storage with humidity control. Whatever the visual condition of the shells, we recommend to always perform a brushing & degreasing of the shells just before having them nitrided.
Information about the nitrided products: to prevent scratches, stains or rust, shells were sanded and cleaned before nitriding. Despite this, irregular marks, stains or oxidized points can occur during the process of nitriding or transportation. A further cleaning step before the annealing treatment and protection against rust after heating should be applied. These final steps will determine the corrosion resistance and aesthetics of the final product. Shellopan will not be able to provide a guarantee on the result of the work done with the shells.
3) nitriding and patent information
Choosing a deepdraw steel with low carbon content (eg DC04) gives need to a steel hardening treatment for the steel sheet.
One possible treatment is nitriding. In the year 2000 the company PANArt Hangbau AG published an article about applying these principles to a metal musical instrument (Conference on New Developments of the Steelpan – Paris – 20/05/2000). More recently, patents have been filed by the company regarding the manufacture of musical instruments made with nitrided steel sheet. These patents are the subject of much discussion and sometimes misunderstanding in the Handpan community. We recommend everyone to study the content of the European patent EP2443625 and its impact on their own individual project.
There is a possibility of using the techniques covered by the patent under license. The PANArt company published at the end of 2017 a document to explain their positioning.
In this period when the question of the patent becomes topical, I (Matthew - Shellopan) chose to share here my personal interpretation of this question:
"PANArt's 2000 Nitriding Publications for the World of Steelpan are the most recognized contribution of PANArt to the history of this musical instrument, and these freely shared publications have been the most informative source of information that all Handpan makers have integrated into their studies.
The patent on which PANArt has been working since 2009 has given birth to a licensing program offering Handpan manufacturers the use of PANArt-protected know-how. This patent protects an improved version of the nitriding procedure that was freely shared since the year 2000. This patent has been the subject of legal debate in the United States and Europe because it has often been considered a trap for makers or apprentices makers of Handpan. Its wording made it difficult for everyone to know if what he was doing could infringe the patent, the nitriding companies did not know how to interpret it or its innovative character was questioned. In addition, it was based on unpublished research and the resulting licensing program was more promoting the commercial advantage of using the "PANArt licensed" than the qualitative advantage of the licensed material.
A patent revision procedure has been requested from the United States and Europe. In Europe, it is a fairly light procedure that tries to secure the weakest against harmful patent filings (for me, patents have become as much tools to secure intellectual property as economic weapons for attack) and every citizen may invoke this review procedure before a certain time has passed. According to PANArt's communications published in late 2017, it appears that they experienced this revision process as an attack against them. The review procedures resulted in a more precise version of the patent. This more accurate version protects a long nitriding program leading to complete nitriding throughout the sheet to give a linear density of needle-shaped iron nitride crystals in a range of 40000 m-1 to 80000 m-1. The patent also specifies a method for determining this linear density and PANArt again offers each maker to have the material he uses tested by an analytical laboratory.
For me, the main question posed by this patent is not legal, it is that no one is able to say if a material made under license PANArt would make handpans "pleasant" or "better". Licensees in the past only use it for its commercial advantage, but actually achieve short nitrites that do not fit in the patent proposed by PANArt. However, there should be some evidence of achievements by other manufacturers with a material made according to the expertise of PANArt and the publication of some research to give a qualitative credibility to this program of license. In the absence of such evidence, this program appears as a marketing product for the development of economic activities. The rapid evolution of the number of manufacturers seeking to differentiate could then make such a program attractive.
Here is a subject on which, I would be happy to be wrong and I would update this analysis if needed!"
4) metallurgical concepts and the importance of the scientific approach
The start of a craft project related to the physical characteristics of metal may be accompanied by a study of these characteristics. We do not have the competence to teach about these but if you feel limited to describe metal with only "hard" or "soft", we invite you to learn about the following concepts:
- Chemical composition
- Yield stress : YS
- Young's modulus and elasticity
- Ultimate tensile stress : UTS
- Fracture elongation : e%
- strain hardening coefficient : n
- anisotropy coefficient : r
- bake hardening and work hardening
- annealing and tempering
- nitriding technology
- compressive stress
- necking phenomenon
- aging phenomenom
- differences between drawing steel, solid solution steel, bake hardening steel, high strength IF steels
Being able to explain the differences in stiffness, strength and hardness is the sign of a good understanding :)
The challenges in our research would be to understand the impact of all these parameters on :
- the timbre of a note and of an instrument as a whole
- each person's style of preparing notes and of tuning
- the durability of an instrument
5) essential tools at every building stage
While some expensive tools can be pooled, some become highly personal such as hammers. Everyone will have their own preferences - this article presents our approach to the subject.
- cleaning of shells: Scotch Brite with grain 180-1000 on edgegrinder, isopropyl alcohol or other degreaser
- nitriding: a rack to space the shells in the oven and avoid distortion
- stamping dimples: male/female press molds + press <20 tonnes. Here we share our tool to help you to calculate the notes and dimples size : shellopan-note-dimples-ratio.xlsx (right click and save as...).
- making bottom shells: male/female press mold + press <20 tonnes + hammer
- shaping notes: rings and support stand, pneumatic sand rammer with different heads and/or other air hammer + air compressor.
- annealing/tempering: oven that can hold up to 400 °C. Electronic temperature regulation system.
- hamering: hammers and mallets set (eg jimmyshouseofhammers) or our tuning hammers. Be carefull with low cost hammer, most of the time it's not cast steel or not hard enough... you may quickly have surface scratch on the hammer. You will need to polish the head to correct the (too) quickly made shape. About weight, 70% of the time I work with 750g, 25% with 1kg and maybe 5% with 500g but that's really personal preference and note size dependant. Quite flat and round shape may be usefull too. We need bigger distance than usual between head and handle because we are working in concave shells, it's not easy to find that !
- tuning: audio analysis tool (eg linotune, overtone analyser, peterson mechanical strobe tuners). Tuning rings + stand to be able to work on each side of the shells (see next point)
- gluing: sand paper, isopropyl alcohol or good degreaser, high thrust caulk gun (polymer glue is thick and you need to put the good quantity in a regular way), rotating plate, mastic cutter
6) handpan tuning stand
You will find all information to be able to build your own low cost tuning stand here. You just need to find a laser cut company and to be able to drill holes and optionally screw thread. For the support, you can use an old desktop or make your own with second hand material. Click on the two pictures below to download the .pdf and .dwg files
7) fablab pricelist and availability
|Shellopan FABLAB - prices list 2017-12||fablab visitors price with french VAT||
price without VAT only for export or intra-europa**
|no shells or material available at this moment|
|next update should be after 2018/02|
** export = sell outside Europa. Custom fees may apply and we are only able to make genuine and accurate invoices. Intra-europa = you need a valid european VAT number to be able to buy without VAT.
8) Questions & Answers
Excel calc tool : are the note size dependent of the steel thickness ? Yes, thicker steel need bigger note size. Just adjust "C4" to change your starting point. Some technic to make shells create unregular thickness distribution, we are making deep drawn shells with hydraulic press to avoid this effect as much as possible.
Excel calc tool : why do you use note number instead of a clearer "note name" notation in your note size calc tool ? Because I don't know your steel thickness, but not only. Tuner skills are changing in time, most of the time with increasing experiences you will be able to tune the same note with smaller area. The border condition that you're creating during the shaping and the note dimple/ratio have big impact on this note size too. You will find your confort zone only after many try and error. I consider that the first size #0 is the biggest note that is possible to make on a shellopan shell (A2) but of course, even me may find that it's possible to make something lower. Step between 2 note number is 1/2 tone, so you will have 3 full octave in my calc tool.
Excel calc tool : what can I do with the F2 cell ? You can control the progression of the ratio between notes and dimples. For smaller notes, if you have a too big dimple, it may be hard to tune the note because you will not have enough space between the dimple and the note border. The color code in colum "K" give you a visual information on this space.
Excel calc tool : can you give me a warranty that I will be able to make a good handpan without changing the value in your calc tool ? No, I think that you need to adjust all these value. I choose the F2 parameter to gradualy change the note dimple ratio from 4 to 5.. this is only to illustrate how it works. The parameter you will choose will give the personal touch of your creation.
Dimples only or dimples & note border : is it possible to make dimples only with laser cut steel of the dimensions written in the excel file ? No, if you cut your molds with the external size, it will be hard to make the dimple only and you will mark the steel on the note border during the process. Some people like it and some people find that it's not good to create the note membrane or for tuning. Again, this is an important personal choice and if you want to make the dimple only, just cut the steel 1cm around the dimple hole.
Choosing a shop press : do you have any advises if I want to use a press to make the dimples ? You don't need a huge press, few tons are enough to make dimple and 20 tons is enough to press a really marked (too much ?) note border