I would like to try the same test with my machine. For the cutting path, I just want to confirm that you used a plunge entry to go down to full depth and then made one pass to complete the square? What was the distance from the bottom of the collet to the end of the cutter? When you said, "not really sure about this one", do you mean you're not sure if it actually cut at 100 ipm or not sure what speed you had it set to? What is your acceleration set to?
Jeremy
http://www.diycncdesign.com/
I ramped until the correct doc cause my cutter is not centrr cutting.
For example I had a 3/4 mdf sheet. The gcode for the .025 passwas like this:
G0 z0.80
G1 f100 x1.25 z0.5
G1 y1.25
G1 x0
G1 y0
G1 1.25
G0 z 1
And yes, I wasn't certain about the 100ipm. I felt it was a bit too slow.
Looks good!
I would do the climb cut passes first and leave about .005"-.010" cleanup with conventional (or climb) pass and see if you get better results. Conventional will usually "pull" the tool into the work (testing your machine's rigidity) but a "spring" pass with climb cutting followed by a finishing pass conventional, so the lighter chipload will not cause the tool to pull in, may help.
The test above was to measure flex more to have a good cut. I usually leave 0.5mm (default in F360) and make a finishing pass a full depth but I didn't thought to do the pass backward. Thanks for the tips; I'm going to test it for sure!
Jeremy: I just measured the cutter and the tip was 1.175in from collet and the LOC is not 3/4 it is 5/8.
Lol!
That crossed my mind too and even if it was veeeeery unlikely, I re-tested my straight edge on the X axis epoxy surface. :idea:
I had an "order" from my favorite helper to make wooden roads so she can play with her small cars.
I was tired of cheaps cutter and found a Freud 75-102 (2 flutes low helix upcut) for 20$ so I tried it. I gained confidence working with my previous CNC and this one is reliable so far so I wasn't worried that much to use a good cutter. This cutter is light years from Chinese spiral cutters I was used to.
When the Z axis is at 0, it cuts ALL the material but I can't feel anything on the waste board. With cheaps cutters, I had to offset 0.002-003 deeper in th ewaste board to have all material removed. I'm really impressed!
The parts were machined in 1/2 BB plywood:
https://youtu.be/GnHc8R0n3gM
The result is pretty good and my daughter was really happy.
Now I really need to complete this dust boot ...
Got bored yesterday and decided to try harder material than wood or aluminium.
I had a small mild steel flat bar epoxied on a piece of plywood from the tests I made before building this machine.
https://youtu.be/n8hd6EaVLlM
I used a 3flutes 1/8 HSS cutter (1/4 shank) to machine a small 6mm x 20mm slot 5mm deep.
This cutter is from China so if anything had gone wrong, this would have been a 4$ loss.
I calculated that with a 0.001 chip load the feed rate should be around 26IPM (650mm/min) and was very conservative with the DOC: 0.010.
Either I got my feed correctly or this cut wasn't long enough (2 min) to over heat the cutter but 10 sec after the cut finished I could touch it with bare hand and it wasn't really hot.
The finish is not as bad as I would have thought, but I could feel each passes with my nail.
Nice job on the steel. I've done the same thing on my wood machine. Not something I'd do everyday, but it was better than my old method of using an endmill in my drill press, lol.
Finally found the time to build a dust shoe.
The router I use exhaust air from the bottom so the chips were flying everywhere.
Attachment 361118
To prevent turbulence caused by the spindle, I made exhaust ports on top of the shoe. I used a ball mill to machine the pocket from the boot to the "shopvac" port.
Attachment 361116
On the other side of the bottom I machined a small pocket to put the brush into. I put thickened epoxy to hold the brush in place. The brush comes from a paint brush I got in a "dollar store". I didn't want to pay a lot since I didn't know if my design was good.
Attachment 361120
I machined Corian for the first time today. This is a 80mm to 70mm fan adapter for a cpu. I should have used a 90deg cutter instead of a ball mill to machine the chamfer. This material produce way less dust than wood!! But I got to be careful with static electricity!!
Attachment 361122
A little waste board improvement.
We had solid surface left overs at work and one was big enough to be used as a waste board. I machined it using the same pattern as my current waste board.
Attachment 362140
I surfaced my old MDF board then sealed it epoxy and glued the 12mm corian on top of it.
Attachment 362138
Should be cured tonight.
This should be more stable than plain MDF.
I don't do alu really often but with this and the rest of my machine sealed with epoxy, I should be able to use mist coolant if needed.
I finally got around to running the same test cuts that you did, so we could compare results. I included a video, so you can comment if you think the 100 ipm looks like the same as what your machine was running. See the results over on my thread.
Jeremy
http://www.diycncdesign.com/
A friend asked me to machine aluminium angles for his late model stock car body. It needs a 3/16 hole each 8 in. I did 0.25 slots too. Not certain that it gives a real advantage but hey, race parts are supposed to be light! Lol
I built a jig I can machine from 0.75 x 0.75 angles to 2 x 2. My first test was a 25 in 1x1.
Not certain which alloy these extrusion are made of but it stick to the cutter like maple taffy... The first run didn't went well as the feed was for a 3 flutes cutter but the cutter I had was a 4 flutes.
Too many flutes and slow speed = burnt cutter with alu welded on it.
Attachment 363352
Realising it, I cranked up the feed from 1100mm/min (43imp) to 130% and it did the trick. 4f 1/8 cutter at 1400mm/min, and 11000rpm.
Still it needed WD-40 cause of the "sticky" alloy.
Attachment 363354
With a roughing and a finishing pass, the slots are 0.249 ant the holes are 0.1880
Attachment 363358 Attachment 363360
Quite happy with the final reslut:
Attachment 363356
Nice machine! I was wondering about taking the same test as you to see as well. ButI wondered: isn't 100ipm a bit too slow? With a 4 flute at 15000rpm that gives a chip load of 0.00167 ipt. I was going to try something like 500 ipm or lower spindle speed - what do you think? Probably the DOC needs to be adjusted?
Or is it better they way you did it -light chip load and larger DOC?
I'm using a 2 flutes not 4 but you are right, 100 ipm is a bit too slow even for a straight cutter.
After some tests, the minimum I'm running now in MDF with this cutter is 150 ipm with a 1/4 DOC.
With "gummier" aluminum, a low helix endmill works better. A high helix endmill, like shown, gives each flute more engagemet into the workpiece, the opposite with what you want. If you got that angle at the local hardware store, it's probably 6063 or even softer 3003.
I would save the 3-flute endmills for finish passes; and use 2 and even 1 flute endmills to rough. The higher helix endmills work great on harder aluminum however, which are the ones that make chips easier.
Thanks for the tips, I think I have an O' Flute style cutter with lower helix than the one from the picture. I'll try it.
I asked the vendor and the alloy is 6063-T5. From what I've seen in my search, it have less than ideal machinability.
In order to prevent alu melting on the endmill tip I had to use plenty of WD-40.
If my friend keeps crashing his race car and need more braces I'll call the extrusion manufacturer and ask them a different alloy or tell my freind to drive a go-kart! LOL