New to CAM and Machining

[drafting3]

Hello everyone!

 

I've been using this forum for a while to locate fixes and advice for what I assume are noob questions, so I thought I'd say hi and introduce myself.

 

I had been working as an architectural designer for residential remodeling for most of my life. I was in charge of creating 3D renderings with virtual walkthroughs for sales, drawing blueprints for the production team, and ordering everything from concrete block to ceramic tile. Recently I realized that I hated everything about it. (An epiphany after watching all three zeitgeists) I got payed great money, but the industry offers humanity absolutely NOTHING. No one needs a $100,000 kitchen remodel, but I've designed and sold dozens. Excess is excessively disgusting, and I was tired of wasting my creativity and engineering mindset on designing lavish living spaces for people with more money than anyone really needs.

 

So, I quit my job and started back to school for a degree in engineering, aeronautical and astronautical engineering to be exact. (figured I might be able to help us get off this rock) A plastic injection company found my resume on my school's website and offered me a job. Now I work in the toolroom, where I mainly act as a toymaker. I handle any and all CNC milling operations, which usually consists of working on the owners racing hobbies. I'm not designing or building spacecraft yet, but I'm learning a lot about engineering and manufacturing, which should come in handy.

 

My CAD background is ridiculously strong, so that part was an easy transition between fields. While I have never used CAM software before, I am extremely computer savvy and typically pick up new software without effort. Machining seems to be where I have the most to learn.

 

We run Mastercam X2 MR2 with a SNK FSP-50v, and I am using G-Wizard to get my baseline speeds and feeds. Even with outdated CAM software and an ancient mill, I've made some pretty cool magic. I'm really enjoying myself.

 

Anyways, sorry for rambling on. I'm sure you'll see me around asking silly questions.

[gcode]

Welcome to the forum

[Del.]

Welcome drafting3!

[Reko]

Welcome, and good luck.

[LaszloK]

Welcome to the group. I hope you find the rewards you are looking for. After 38 years in this industry I am looking forward to the simple life living in my cabin in the woods. Good luck!

[mkd]

sounds like you will be running your own nc code. great way to learn!!

 

manufacturing can be much leaner and meaner than what your used to dealing with. (at least in my exp)

[Jayson Kramer]

Welcome to our second home or maybe a 3ed for some.

[CADCAM3D5AXIS]

Welcome To the Group and Pit stop area. Enjoy making the toys because aren't they all toys anyway ???

[drafting3]

sounds like you will be running your own nc code. great way to learn!!

 

manufacturing can be much leaner and meaner than what your used to dealing with. (at least in my exp)

 

yes sir! i am the alpha and the omega, the beginning and end of all cnc milling here. it's nice because i know every detail of every cut, but when there is a mistake, it's 100% mine. when i first started here, i only did CAD and CAM. then one day the cnc operator was late to work, and since i had been watching him, i just started milling parts. instant promotion! the machine operator was fine with it, i think, because he prefers manual mills anyways. until i got here, they couldn't get the ATC working. they needed someone who could "talk to computers", and i was their man.

 

i've been playing with g-code, because i felt it was important to know what i'm sending to the mill, rather than blindly letting mastercam handle it all. i will tweak the g-code directly from the controller now, which is a nice time saver.

 

one thing i've been doing recently is using MDI mode on the mill to do simple operations, mainly facing or cut-off operations. i understand g-code now to the point that i could hand write code if i had to.

 

i've broken many tools, but most were because of speed/feed issues, or running the tool well past it's lifespan. there was one incident of "press fitting" a 1/2" drill bit into aluminum, which was also when i learned what the "H" parameter in g-code meant. up to that point, i thought the height offset was directly linked to the tool being used. thankfully, it was just a HSS jobber drill, and the aluminum billet could be saved.

 

 

 

i do have a question about tool life. i've been working with mainly HSS, as the owner here thinks carbide is the arc of the covenant. it seems like my HSS cutters don't last long, even in cold-rolled 1018 steel. i've had cutters get dull and need replaced after about 2 hours of machining. is this normal? are my speed/feeds wrong?

[The_kid]

You can ususally run carbide about 3x speed and at least 2x feed. its natually not as sharp so if you are working with plastics HSS is the way to go. But if you are working with any metal carbide without a doubt. do yourself a favor look up a book called the machinist ready reference. I use it on the shop floor a lot. this has basic feed speeds calcualtions. But when in doubt push it till it breaks then back it off 10% then run it at that. You see a decrease in tool life if you don't run the tool hard enough same as to hard. You will figure out how to tell by chip formation what you need to do as well has how it sounds.

 

BTW welcome and good luck.

[drafting3]

from what i've seen, HSS works great on aluminum, plastic, and wood. i've cut on 6061 for days with the same HSS cutter and never had any burring. anything harder than aluminum, and i'll be using carbide exclusively from now on.

 

i just found (yes, i found) a toolbox tucked away behind the machine. besides a collection of various HSS and carbide endmills, it has a 1/2" 2-flute 90 deg indexable carbide insert mill, a 1" 2-flute 90 deg indexable carbide insert mill, a 5" 7-flute 90 deg indexable carbide insert mill, and a 3/4" ballnose carbide insert mill. i'm pretty excited about these "finds", and can't wait to put them to use on my next steel project.

[mkd]

2hrs in 1018 steel with HSS sounds like a pretty darn good setup to me as far as speeds and feed and toolpaths.

 

i basically agree with recommendations above.

 

it is arguable as to the benefits of carbide in aluminum in a prototype environment, particularly as cutter size increases. HSS will yield great results and it is a bit sharper to start with. if you're getting used to programming HSS cutter are cheaper to snap.

personally i wouldn't bother with HSS endmills in any cutter under .500". go straight to carbide.

 

welcome to the best forum ever. a wealth of knowledge and help here.

[mkd]

note:

carbide cutters, steel workpieces and water based coolant are not a good combination above 250 surface feet per min.

 

use air blast above this speed

[drafting3]

thanks. i'll take all this carbide advice into consideration on my next project.

[The_kid]

make sure that you use ramp in for your indexable endmills as most of them will not center cut.

[drafting3]

make sure that you use ramp in for your indexable endmills as most of them will not center cut.

 

i've been studying their geometry. i definitely have to take a few things into consideration since only a small portion of the endmill actually cuts. (ramp angle and using depth cuts)

 

this brings up another good question. i've been using a lot of 2f and 4f center cutting endmills, but i still ramp/helix those. is it practical to plunge cut with these? i assume feed should be turned WAY down for this? i understand they are center cutting, but it doesn't look like any of them have much chip clearance at bottom dead center. i've been ramping with 2 degree slope using center cutting endmills. does center cutting allow me to make my approach steeper? will a steeper approach wear my cutter faster?

[gcode]

Ramping is the preferred solution.

Plunging should be avoided if possible.

If I must plunge, I will try to clear the center out with a drill first.

[drafting3]

If I must plunge, I will try to clear the center out with a drill first.

 

that's what i've been doing. if i need to plunge, i predrill the center. then peck drill with my endmill to keep from having a wadded up mess, followed by the pocket toolpath.