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Safety and liability
In general please consider the safety implications of building a machine regardless if it is a commercial or hobby project. Some basic questions to ask yourself: Where will it be put, who will have access to it, will they use it safely, what will happen if something goes wrong?
When you deliver a machine or even parts of a machine commercially, you as a seller take on certain safety responsibilities as the product you sell need to fulfill the health, safety, and environmental protection standards that governs that type of product. This is true for all products and can not be easily waved away with an "on your own risk" type of warning.
You as a seller needs to figure out which standards your product needs to adhere to and then make sure that it does! After you have done that you can declare that your product conforms to the applicable standards by putting a CE-mark on it.
Many small business owners are intimidated by the CE-marking process and either hire someone else to do it to try to cower their backs or skip it entirely and hope for the best.
The drawback about outsourcing the safety-work is that you as a machine developer does not do the risk-evaluations yourself and many easy safety design improvements might not happen since the work is done as a afterthought rather than being part of your development process.
Since Fabricatable Machines is a open hardware project this opens up an interesting opportunity to handle the safety evaluations and design considerations publicly instead of treating it as a company secret. I hope that this will allow more people from different perspectives to contribute their views and I also believe that the resulting "guide through the CE-djungle" will be help many others since the rules and problems are the same for everyone. I suggest that we document the process of how do design safe machines openly, from a regulation novice perspective.
What is considered "safe enough" to be legal is a moving target an develops as time moves on. So this guide needs to be kept up to date as time moves on.
As a first case I suggest we look at Humphrey v3, a large size CNC milling machine sold as a kit to be assembled by untrained volunteers in a makerspace. It uses an AC 220V to 36V 10A DC power supply for all motors and electronics except for the spindle which is powered by a variable frequency drive with 800W AC at 220V .
Alternative to wikipedia CE marking flowchart from here
List of the directives Find which directive that applies - Wizard
Directives that seems to apply to Humphrey v3 when completed
- EU Machine directive This will be the big one.
- Low voltage directive Covers products using between 50-1000V AC and between 75-1500 DC. The power supply, VFD and spindle are inside those ranges.
- Energy-Related Products (ErP) Directive It uses electricity. Duh.
- Electromagnetic Compatibility (EMC) The spindle and VFD creates significant electromagnetic noise
- Restriction of Hazardous Substances in electrical and household appliances (ROHS) This is most known for restricting lead in electronics components.
Many of the relevant directives has to do with components that is bought pre-fabricated and might already be CE-marked. So as long as those components are used inside their approved safe boundaries they should not cause big problems to our safety-approval. However it is necessary to investigate this.
Offical homepage Full text Machine Directive 2006/42/EC 400+ page guide to the Machine directive
- Humphrey is clearly classified as "machinery" according to article 1(a) and 2(a).
- Humphrey is NOT in the ANNEX IV list (circular saws and other extra dangerous machines) and can therefore (according to article 12) be assessed by the manufacturers internal checks (according to Annex VIII), meaning that no third party certification is required.
- Annex VIII requires the manufacturer to draw up a technical file (according to Annex VII, part A) and make sure to follow it when making the machine.
- ANNEX VII A describes what documentation we need to compile to proves how Humphrey complies with the directive. It is all sensible things that we would like to compile and document publicly anyway.
- The next step is to read through the directive text and tag to paragraphs that are relevant to Humphrey. This sounds worse than it is, the text can probably be read through in a few hours.
- The result should be compiled to a list of a list of "the essential health and safety requirements which apply to the machinery"
- Do an iterative risk assessment and risk reduction and document it (use ANNEX I 1 as a guide).
We also need to:
- Write instructions for assembly, use, service and decommission.
- Perform tests to verify our theorizing and find missed safety risks
There are probably hundreds of ready procedures to follow when doing a risk assessment of a manchine, perhaps we can find an open one to use?
When performing risk analysis, remember to consider the machine in all stages: Being assembled, running, during service and during decommission. It can also be useful to look closer on different parts of the machine and different usage scenarios to find hidden risks.
Potential procedures
If someone where to sell only the mechanical parts to build Humphrey and not the electronics, then only the machine directive seems to apply. And there are special rules about responsibility in the Machine directive which apply when someone is selling parts to build a complete machine from. This is due to that the seller will not be able to do the final safety-work.
Read more about a Declaration of Incorporation
An example of such a declaration
However it is still worthwhile to look at all the relevant directives for the complete product since the intent of this initiative is that it should be easy to build a safe complete machine and not just to try to push the responsibility on someone else.