End Mills and Feeds n Speeds

[Rikk]

I just buy from my local supplier W. L. Cooke Ltd not sure if they do mail order.

Just have a google lots of decent suppliers about, but as I'm just buying small/hobby amounts I've never gone further than my local.

Problem with small endmills is you need high speeds to get any kind of decent feed, do you have any images of what your making people may be able to suggest other ways of doing things.

If bobcam is that bad I'd be talking to them about some kind of refund, have to admit after reading about their products and sales technique I'd never touch them.
On the other hand I'm just about to buy sprutcam, great product and more importantly the UK distributor is a really nice guy and VERY helpful/knowledgeable.

[bebob1]

@Bob
Thanks for the advise, I will be looking into runout.
Even when doing 10mm roughing/finishing I have yet to get a really decent finish, but of course there are other factors I need to consider too.

When we spoke to the Syil distributor in UK, we sent them image of the types of tools that we wanted to produce and even went and visited a local user, all said our parts were simple and should be no problem. As a complete noob to CNC, we put our trust in Syil and it was them that recommended that ER40 was the best for applications. However, knowing what I know now, ER40 is perhaps not the best solution, more so on the small end mills as we most of our work is going to be using 1.5mm drills and 1, 2, 5mm end mills. Maybe its a bit harsh, but I think we were seen coming.

For tool paths, we are just using a plunge, at the moment.
When I started looking at CAM solutions, we wanted something that would integrate into Solidworks. I tried lots of software, open source, free and subscription based too and have a spreadsheet of them all.
BobCAM are VERY aggressive on sales and dropped their price by over 50% to get the sale. In hind site, was it the best purchase? maybe not. When they did the demo, they used our supplied SW file and it looked a breeze. It wasn't a perfect demonstration in terms of click, click, click done but I wasn't expecting it to be. We used a local training BobCAD trainer, who had a very good training guide, but was just reluctant to teach based on our application. When we did get him to try, he struggled to get some tool paths to create and had no idea why. There were months of going back to him and BobCAM to get support, unfortunately, all BobCAD were interested in were trying to sell us their extended support and training.
Anyway, they finally gave in and did a live support call and even they had issues getting it too work and this just uses simple pocketing and some drilling routines.
The expectation that BobCAM could be used straight away on our part was torn apart. We now have to add a bunch of additional planes and boundary sketches to get it to create paths. Luckily for us, we built an awesome app which builds our tools in seconds based on just a couple of dimensions.

So, as it stands, we got BobCAM to produce tools paths but had to move to the next stage of making the resultant gcode work through MACH to our Syil
Reliance/assurance that the default milling parameters in BobCAM we sufficient have also taken a battering.
I appreciate that I now need to move further and perhaps choose better milling routines like spiralling to reduce stress.

I certainly learnt that trying to drill 26mm deep in this material with a 1.5mm drill bit in one pass just does not work and pecking at 2mm steps seems to work much better.

For cutting fluid, I was finding that although it appeared to be working, it was also causing chips to collect after ejecting and without a constant air supply to clear them, it was actually have a negative effect in comparison to running the same job dry (on a 10mm rough)

As for material, its a face palm moment.
The decision was made to purchase a bunch of blanks for us to use, from China Although they are specified as T6 6061, in reality they could be anything. The old addage you get what you pay for rings true.
I have found a new single flute in a box of old bits, so I will certainly give that a go.

Appreciate your feedback.

Simon

What CNC machine do you have specifically? You mentioned syil somewhere? I dont know anything about them, but I dont think their spindles can be any more horrible than other machines. Even cheap small benchtop machines can do reasonably. Get an indicator, the type you use to square off your mill, and point the measurement at your actual cutting tool. Then rotate the tool slowly (manually if you can spin the spindle) and read off the maximum deviation. This is the runout.

BobCAD cant be too bad in terms of toolpath generation. I dont use bobcad but I am sure it can do helical or ramp entry? This is better because many end mills are not center cutting, and even if they are, it is a lot easier to ramp in at an angle. Otherwise, if you are plunging, you better be going real slow. Plunging in aluminum with a 3mm end mill, 6061T6, 3000rpm, I usually do 25-30mm/s max (I recently made such a hole). Like all CAM software, there is a learning curve. The most important thing is it does the job you need it to do and this may involve learning how the software works. Its like learning a new language; mastering your mother tongue does not guarantee you will be any good at another foreign language so you will have to let go of expectations and follow the rules of the new language to succeed.

For drilling you can follow the guides. Normally you want to feed it with the correct speed so it is constantly cutting to generate continuous chip/swarf. THen you generally want to retract completely when that chip length is grown to equal to the cutting length of the drill bit.

Why not buy materials from a local source? I am sure there are metal workshops and foundries that sell material like bar stock or extrusions.

Also what do you intend to do mostly and what tools? You mentioned use of small tools. If you always plan to use small tools you may want to invest in a high speed spindle more optimized for using small tools. E.g. people doing jewelery engraving work with small end mills or engravers use high speed spindles instead. The default spindle on your mill probably cant go too high speeds and is more optimized for larger scale machining or parts using bigger end mills and say cutting steels which require slower speeds.

[williamsmotower]

You need to ramp the cutter in. It's getting gummed up in your plunge.

You can try spraying wd40 on piece before plunge.

[axis_control]

I am relatively new to CNC and am struggling with the whole feeds and speeds selection as I am a metric user (sorry ) always seems the good information is in imperial, which has to be converted, so I have been relying on various tools such as BobCAD Machinist Toolbox, The Machinist Calculator and a couple of online source, all of which produce varying results.

I hope this wonderful software helps. I am a metric user