CNC Fundamentals - Ep. 2 - How Machine Side the Bottom Side

[@NerdlyCNC]

Im aware the stock was a larger than necessary. It wasn’t worth dragging material off the rack, setting up the saw and then cleaning up the mess and de-burring 2-3 blanks for this short demo. We could’ve easily just made this twice as thick the point was to demonstrate the process. Cheers, Jason This demo part was made from some material that was cut for another project and never used.

[@robinsondrob]

This is useful, not many people do the bottom side on here. Thanks or sharing

[@machinists-shortcuts]

It's good practice to set the end stop close to the centre of the reference face. It helps with future referencing and negates any out of squareness.

[@makun16]

If you bend the metal bands that comes on crates into springs they make great parallel retainers.

[@NerdlyCNC]

great tip, i've heard this before....it would probably make for a good "tips video"

[@brianwaayenberg3099]

That’s a great/cheap idea!

[@baxedm9806]

Can you share where you got your 11/16" x 14mm stepped vise keys? I'm assuming you use those to align your tegara 660U vise to the Syil table slots.

[@mathavanpackirisamy4239]

Nice machining.... Why don't you ues face mill for remove material in roughing..??

[@TheHelicapt]

That machine is a beast

[@johannglaser]

Would have loved to hear you voice over during the machining and discuss tool choice (why endmill and not a face mill), paths, ... and also explaining the steps by the machine, announcing next steps, ...

[@NerdlyCNC]

editing some dedicated videos for that now

[@AmericanMakerCNC]

Thanks for all your great content! I have tried this 1-2-3 block trick with a vice stop several times without much success. The hat removal works great! But when I try to chamfer the bottom of the part, the left edge chamfer is always too deep or big and the right edge chamfer ..... well there is none. The chamfer mill is too far off the right edge of the part and never makes contact. The only way I seem to have success is to touch off on the hat (G55) and remove the hat, and then touch off on the part (G56) for the chamfers. Do you have any ideas why the 1-2-3 block is a fail for me when it comes to the bottom chamfers? I would love to get this to work. It simplifies and speeds up setups. Thanks!

[@jurgenboucher116]

I like the rubber band, especially on C-axis and A-axis 😉

[@paulhudik4836]

how do you keep your machine so clean

[@TamilselviYogaraj]

Dont use your machine.

[@johnspathonis1078]

Hi Jay Another great video! With the end mill are you using a DC12 collet?

[@Chris75169]

I just rough off the salvage at the bandsaw. Fly-cut to final thickness. Then run the chamfer program for cleanup. If doing multiples, the material would be thick enough to run opposing sides then split and finish.

[@rayp.454]

Or start with thinner stock. 1/8" oversize is plenty for gripping top and finishing bottom. Maybe save some material cost at the same time.

[@lilchirp4846]

What do you use to shrink in those tools?

[@advancedretention9859]

The chamfers look really rugged... did you go back and clean them up with a finishing pass?

[@NerdlyCNC]

Nope. Part was as machined. First pass

[@MrRctintin]

Hi, why did you remove the excess stock with an End Mill and then use a shell mill to finish? Any reason why not to just use the shell mill taking skims off until the desired height is reached?

[@85CEKR]

You end up with large chunks of metal flying around I your machine when you do it that way, it might work fine 9 times out of ten but that one time if flies between the part and your face mill your really gonna regret it.

[@HH-Machining]

If you machined the part deep in enough in 1st OP, wouldnt face milling be faster to remove the excess material?

[@Kyran31]

The reason he milled it using an adaptive tool path is because he wasn’t left with pieces of material that weren’t attached to anything flying all over the place getting stuck between the workpiece and the tool, I learnt this the hard way when I was starting out a couple of years ago

[@85CEKR]

@@Kyran31 ya generally anytime you machine chunks of metal off your asking for trouble. In production I like to HEM anything that could turn into shrapnel off and them face mill the rest off, depending on the part it can save time.

[@samboles8796]

For this part in aluminum with that amount of side stock absolutely (2-3 horizontal passes) But speed is overrated especially when it’s not production. What I mean is does 3 minutes really matter If you’re making 3 parts? The way he approached this part was perfectly fine. Unless you’re boss is an ahole My 2 cents

[@kimon777654985494654]

Dont offset the tool, offset the workpoint, unless you want to make the next part again (You foget the tool offset) :)

[@TrPrecisionMachining]

good video

[@BuildItAnyway]

very informative!

[@eusebiupruna6897]

👋 hello, cand gove me some specs for milling aluminum pleae? As feedrate, rpm, etc. O have a small cnc machine from step-cnc and it doesn't sound too good when i insert what the books or standards say

[@gamble1997]

The only reason you use the 123 block then put the material is is because it's more accurate than just getting xyz0 off the stock part?

[@NerdlyCNC]

You can’t always reach the actual reference surface on the part because the remaining stock material was in the way.

[@gamble1997]

@@NerdlyCNC Oh I get it now! Thanks. What tool path did you use to clear off the of that stock? And by using the that Z zero, how to you ensure the tool doesn't take too deep of a cut?

[@Hanal503]

You have there extra mat...for 2 or 3 pcs?😅😅😅😅😅 Or 4? Fantastic😅😅😅😅

[@BecomingOffgrid]

I cut all my parts 3 thou to short, what machine setting can I use to correct it?

[@NerdlyCNC]

which control and what machine?

[@BecomingOffgrid]

@@NerdlyCNC lol, there is a great need for a sarcasm font. I was only kidding to get a chuckle. I do have an X7 with Siemens control.

[@reedmike1012]

Using mastercam I machine molds and always skim top and set z after with probe. Cut the core and cavity on the same piece of 5×8 stock 12.25 long usually. then cut em in half on a band saw and then manually mill to size then do the water lines, eye bolt holes and engraving. Never work from the bottom. But if the part is good and process is efficient then it doesn't matter lol

[@NerdlyCNC]

thanks for the run down.....i'm always interested in seeing how others work. cheers,J

[@reedmike1012]

Your welcome. Part looked nice as long as it's in tolerance right? Lol

[@happygilmore2100]

Isn’t there a better way, or a more economical way to hold the material, as the amount of material taken off, could make 2 of those parts.

[@manishchauhan9495]

How to align round workpiece in Vmc

[@nickvasquez85]

Cutting parameters?

[@NerdlyCNC]

I’ll share in upcoming vid Nick. This is somewhere around 10k / .600 doc / .060 woc / .0035 ish ipt

[@Daniel-vq9zb]

Working with the Z offset on top of the part will save alot of mistakes over time

[@NerdlyCNC]

I prefer the bottom. So that when the machine reached lowest Z height I can compare to part height. But I use the top sometimes. To each his own.

[@Daniel-vq9zb]

@@NerdlyCNC atleast with mastercam linking parameters it would be fairly easy to rapid through your part if your zero isn't on top or above the part, may vary for what you use

[@machinist7230]

@@NerdlyCNC the only time I work "bottom up" is with inconsistent material thickness and with no flycut/face mill for whatever reason(fiberglass, for example, looks horrible when you do this). Everything else is top down. I will say that I frequently check clearance between the top of the jaws and the endmills using a gauge block to avoid contact - piranha jaws are expensive! I've gotten as close as .003 to the jaws, but I usually try to keep a .015-.020 clearance.

[@alexhorne4189]

@Daniel How so? For most second op work I program, I program from the bottom. Absolute top of stock and incremental for other linking parameters. I also use a probe and tool presetter so I can trust my tool lengths and z location to be accurate enough for 90% of the work I typically run.

[@Daniel-vq9zb]

@@alexhorne4189 I'm not saying it's impossible I'm just saying having your Z set at the top of the part will eventually save you from running into something, im sure working off the bottom is fine 99% of the time but it only takes one time to scrap something lol

[@justindewoody]

What machine is that?

[@NerdlyCNC]

all info in description

[@makosharkcnc7730]

what a wast of material / you think?

[@NerdlyCNC]

Lmao. This was a demo part. But since everyone is bringing it up. A good video topic may be “machining efficiently” Cheers, Jason

[@85CEKR]

With cheap materials like aluminum, you save lots enough time using that procedure to justify the waste.

[@andreasbrunnhofer]

Why dont you just put the part in, take a light facing cut, measure the thickness and then input this measurement into z? Thats actually how you would do it when you have to make parts with narrow tolerances.

[@michaelbeale42]

Really. Hahaha

[@michaellavazza960]

Seems like a ton of waste!

[@NerdlyCNC]

in a perfect world we'd definitely try to use the smallest piece of stock possible....but i had some of these cut to size already.

[@michaellavazza960]

@@NerdlyCNC and I know NOTHING so don’t take it as being critical :). It was really cool and I learned a lot!!!