As a newcomer to the world of CNC and milling, about to embark on my first build - I thought a health and safety thread would be useful! I thought I'd start it off with a couple of questions I have been pondering. First, I have to say that this community, and especially the staff members at openbuilds, leave me in no doubt about the importance of safety which is a great thing. For example there is no way I am going near a laser without the right glasses, and an E Stop, limit switches are top of the parts list for my build! My questions are more about the materials I want to mill. I definitely see myself using my new build for making isolation path PCBs for my electronics. I had thought to use FR-1 circuit board blanks which are a hard paper (HP) laminate which I understand is more suitable for milling. However, I have seen that many people are using FR-4 which uses Fibre Glass cloth laminate. Is this safe? Second, the question of MDF. Numerous comments about exercising caution cutting MDF, yet most, if not all of the spoiler boards are MDF. I anticipate that my spoiler board is going to see a lot of action until I jump up the learning curve - so I was wondering if there are safer recommended alternatives? Finally, I realise that very much connected to this is the question of appropriate dust extraction. Can any of the experts comment on this, perhaps suggesting something appropriate for first time hobbyists. I haven't seen any examples of attachments to the Z Axis that remove dust from the work zone immediately - would this make an interesting project addition? many thanks,
Hi Bit53b, Very good points you are making here and I am pleased that you have started this topic. Safety is paramount. I generally always use the copper clad fibreglass board for pcb's and it would certainly not be safe to inhale the dust produced. Consideration should be given to the type of spindle being used as some spindles have internal cooling fans which expel air downwards, towards the work - this would stir up the dust and could possibly create a very dangerous situation for the machine operator (and any by-standers). With my system the dust stays put on the work and is then subsequently removed with the shop vac - this in itself may not be a totally safe method as I have little idea of the minimum particle size which the shop vac actually filters. However my shop vac is located in a lean-to adjoining the workshop (same place as the compressor) and ducted through so any particles set loose into the atmosphere should not affect my health but it may not be such good news for Bambi outdoors. With regard to MDF - a suitable face mask is recommended by the manufacturers to be worn at all times when cutting the material. The standard ( e.g. B&Q purchased) material often contains formaldehyde in the bonding agent but there is a much safer alternative which is sold, here in the UK, by the brand name 'Medite' - this uses a water based bonding agent and is much preferred by laser users. Dust shoes, as you have mentioned, are generally used with CNC machines and there have been 1 or 2 designs already described on the forum. I do have a dust shoe but, because of the type of work I generally do It seldom gets used nowadays. Tweakie.
thanks Tweakie, that's really useful to know. do you know if the outrunner-type spindles expel air downwards? I was hoping to have a go at one of those. I'm really interested in those builds and the software projects to control the speed.
The ones I have don't have any internal fans they just rely on 'prop-wash' for cooling. Don't know for sure but I suppose if any outrunners are designed to internally create air-flow then it would make sense that the flow would be in the opposite direction to the shaft. Tweakie.
