I did use CC the first time around. Thank you for suggesting MeshCAM! I’ll definitely check their recommendations.
For mother of pearl I slow the plunge rate down to 12 mm, it’s quite brittle and I did note most of the breakage was on the plunge. I’d begin by lowering your feed in case deflection is your principal issue.
Please also check with the vendors who make endmills that small — esp. the Precise Bits folks.
As far as small bits check out Carbide Plus (aka drillman1) on ebay. These are quality bits at very reasonable prices. Some of the Kyocera bits he sells are less than half the price as through the Kyocera store.
Precise Bits, which Will refers to, are very high quality but pricey, in the smaller sizes, when honing your techniques. That said, there is a lot of “value added” with the extensive information provided on the site.
I tried the RPM and Feed Rate you recommended Byrne and it worked like a charm! I couldn’t believe it! No breakage at all, but I can see that the bit quality is not great to cut brass with. I’m seriously over the moon though!! THANK YOU SO MUCH!
So basically what you’re doing is called micro-machining, it’s when you get into diameter less than 1,5mm. I haven’t done any so I can’t help about f&s but I’d advise buying some ultra high precision ER11 collets with 1 micron or less run-out if you can, the lowest the better, thought I wasn’t able to find some ER11 rated with less than 2,5 microns.
You can read about run-out here:
The thing with micro-machining is that any tiny amount of deflection becomes significant, run-out increases deflection, deflection increases your chip load, it goes over what the endmill can handle, and since carbide is very brittle and can’t bend, it’ll break very easy.
So that’s probably one of the thing you can address quite easily, and it’s rather cheap.
The other rather easy thing to do is to reduce the stickout of the tool to as much as possible, so that you have just the right length to do what you need, this dumb thing will reduce the deflection of the tool also quite a bunch depending how long you had it sticking out.
Thank you so much for sharing this, Raxor! It was really useful! I reduced the “stick out” of the tool as much as I could and I feel like it’s doing a lot better! x
I don’t know if this will help but I remembered a post from a few months ago from someone who is milling very small parts. He may be able to answer your questions.
To reduce the projection of the bit from the collet you can even trim some off the end of the bit (the top!). I do this especially when the bit I need only comes in 2.5" lengths. I do this using a diamond cutting wheel on a Dremel tool. Clamp the bit down on a moistened paper towel so as not to heat the bit up. Cut as square as possible so as not to introduce asymmetry which might affect the balance.
I have been having similar issues. Can’t wait to see the responses!
I suggest entering this information into a G-Wizard (trial) and seeing what it gives you for settings. That’s where I started when I used my Nomad Pro to carve silver. I did 3D roughing with .8 mm end mill and 3D finishing with .3 mm ball nose bits. I bought these carbide bits from eBay, Alibaba, and Amazon for cheap and I get many uses from the bits. Here’s a screenshot from a book I’ve written but haven’t published yet.
You have information on endmills willing to share regarding cutting metal thru to make charms??
With the information above everything worked perfectly well. There are also a few recommendations for great end mills that’ll do the job perfectly well xx
Would you share on what bit you are using?
I’m using a 0.3mm bit that I bought from Cooksongold in the UK. It was made for a Magic70 cnc machine, but it worked great with the Nomad
Interesting thread, getting in to micro machining too.
Currently have a .25, .5, .75 and 1mm tapered bits.
Looking to really start on pine and cheaper woods as I learn. Hopefully will move on to ali as I want to make jewellery
Personal opinion, assuming that bits are 1mm and smaller and not a fraction of an inch, they will not give you great results in pine, it is too soft. The small bits will basically give you a scratch in the wood with fuzzies on each side. No crisp lines. I would suggest a harder wood like maple to practice with the smaller bits.
Good point I hadn’t considered that pine might be too soft.
Yes I’m working in mm
I’ll look around for some different woods to try too
I don’t have much knowledge about the jewelry production but I use my Nomad for production of chips. I’ve been working with PC (or polycarbonate material) for the past month and I’ve made use of 0.1mm and 0.2mm flat end mills for carving out the channels. For both these mills, I kept the spindle speed constant at 10000rpm. For 0.1mm flat end mill, I plucked in the feed rate as 76.5mm/min and the plunge rate as 2mm/min and for 0.2mm flat end mill, I used the feed rate and plunge rate as 186mm/min and 7mm/min respectively. These values worked perfectly for the material I’ve chosen. I cannot guarantee the same for gold but it’s worth a try. Hope this helped!
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