[louieatienza]

I don't recall seeing a thread dedicated to problems arising before, during, and after construction of a DIY CNC router, and thought it might be of interest to others, as well as open up discussion on certain topics:

Overplanning and Over-Designing
I'm sure there are many here who enjoy the process as well as the fruits of their labor. I'm as guilty as any in this matter. I do wonder how many of those in this category actually produce something for profit or hobby, or whether the act of building a machine is not a means to an end but the end itself. Obviously, constant modifications and similations can save a lot of time down the road, especially when expensive components are used. But there has to be a breaking point where too much time is spent in the design stage, and the machine remains as "vaporware."

Cost of Materials Not Fully Considered
Scrap metal may be inexpensive, but having them fabricated into what is needed may not be. Some processes are very difficult if not impossible without a fully equipped shop, and consideration for the cost of "sweat equity" needs to be taken. Bonding and leveling supplies like epoxy are very expensive. The number of even common nuts and bolts can be astronomical, and if can't buy them in bulk, so is their cost. This is one thing where a little over-planning can be a good thing, as a bill-of-materials can be generated from most CAD. Tools, abrasives, blades, drill bits, taps, solvents, finishing supplies, even electricity and water all add to the cost; though I'd bet a lot of jobs don't have these costs factored in.

Inexpensive Electronics
There have been many threads here concerning out favorite imported CNC drive chip, and some good ones. Usually, the cheapest of these imported drives cannot handle the voltages needed to efficiently drive the steppers they are normally sold with. Here's one area where not skimping can pay big dividends down the road, as I go over briefly later on here....

Moving Rail Versus Moving Bearing Blocks in Z Axis Carriage
I personally feel that the moving rail design can be stiffer than the moving bearing design. I would postulate that the moving bearing block designs work best with relatively smaller Z axis travels, while the moving rail design would work best for larger Z axis travels. I suppose linear components and construction of carriage and saddle play a big role. I also think the moving rail can cause some design issues that would make it more difficult to build than the moving bearing design. That said both methods have been made to work, though for large Z travels I still think moving rails are the way to go.

Software Not Considered in Machine Cost
I see this quite a bit. A killer machine is made with top notch components and great workmanship. High end electronics and mechanicals are used throughout. Yet these machines are run using two-decade-old software for CAD design and workarounds in the controller software; or the machines are run using somewhat limiting "freeware." I honestly don't get this. If simpler parts are what is needed, simpler mechanicals and electronics could possibly get the job done as well, and the money saved can be used for software that is likely easier to use, has more features, and can handle more intricate work. I guess I'm not as up-to-date with freeware packages, and they're probably a lot easier to use than even a few years ago. But my experience has been that the learning curve is a lot higher, and the navigation may not be as intuitive.

Mismatching of Leadscrews with Stepper Drives for a Given Application
This is another area where potential problems occur. I've been bitten by this bug early on as well. Mainly, why do my powerful 425in-oz steppers not have enough oomph to move my relatively light gantry any faster than 50ipm? And if I try to, it stalls? Maybe the stepper was a mismatch to my 10tpi leadscrews that I bought real cheap. Thank God I did because I ended up buying screws again - multi-start leadscrews. Using a bigger power supply and better drive literally more than doubled my performance. I'm definitely not an expert on sizing steppers to a particular situation but have tried to learn as much I could, and have made better decisions with later builds. There is great information by Mariss Freimanis on the GeckoDrive website, along with some equations that would get you closer than any guesswork would.

The Fruitless Pursuit of Chasing Unattainable Accuracy
One thing that I've had to wrap my brain around is that everything in the CNC world is built to a specific tolerance. It is the exception, not the rule, that zero-tolerance parts exist. And they may only exist under certain conditions or variables. From the steppers or servos, to the screws, to the linear rails, to the support bearings... even the spindle bearings and the endmills used, all contribute some form of "error." Even if you did buy the most expensive components, it would have to me mated to parts made to the same tolerance, and kept in a controlled climate. And even then, the parts may have some flex or play in them. It's not a trivial thing for a commercial machine to make a part to within .0005" or even .001", and even then you'd be at the mercy of the measuring device used to check.

The Damn Absolute I,J/Incremental I,J Setting in Mach3
This damn setting has burnt me a few times, and I don't seem to learn. But to me it appears when a fresh install of Mach3 is done it defaults to Absolute, whereas the post-processor of some common CAM uses Incremental. I do have a CAM that has a configurable post-processor and can change this if needed...

Feedrates Too Slow/Spindle Speed Too High
This seems to be pretty common, especially in materials like Aluminum or Plastics. Commercial machines have much lower spindle speeds than routers, though they do have much more horsepower. This problem however may not be avoidable for some, with fixed-speed routers, or lower horsepower routers that do not have enough "guts" to power through materials at lower speed. A couple solutions would be to use bits or endmills with lower flute counts, or increase the feedrate. If the machine is not ridgid enough, smaller depths of cut may be needed along with the higher feedrates.

Wrong Bits Used For The Job
I started a thread on router bits and endmills, which is stickied to the top of this forum. While it can get expensive, it's always best to use the right tool for the job. The work will be cleaner, the tool will last longer, and your machine will run better. Of course, one could get carried away and have hoards of unused bits. The best thing to do would be to purchase bits as needed, instead of buying prepackaged sets. On the same topic, I am a firm believer in buying the best quality bits possible. There are many cheap imported bits on eBay, and my experiences have not been good. Believe it or not, high quality bits from reputable makers can be had for not much more than the cheap bits, and it just takes a little digging to find them on eBay. The aforementioned thread list brand names for searching.

LookAhead My Be Set Too Low in Mach3
I find I get better performance by increasing this number in the General Config screen. Apparantly it is set default at 20. Even 15 year old computers have enough processing power to set this number a bit higher. Some testing may need to be done. I have mine set at 192, though the max is 1000. Too high will cause problems. If you do a lot of 3D work this may save you a lot of time, especially if you can set you CV distance very low and have relatively high acceleration settings. There have been some reports of "smoothing" of certain details, which may be related to the CV settings. I have my CV distance set to 20 and my acceleration at 30, and do not experience any corner-rounding. A slightly oversized bit may also cause slight corner rounding as well...

Climb Versus Conventional Cutting, and Rough and Finish Passes
I find I get the best results, and less chatter, climb cutting as opposed to conventional cutting. I also find that the bit or endmill is less likely to "catch" the workpiece, since the tendancy is for the bit to push away from the cut line. Knowing this, I always leave a small amount for a finish pass, which gives me less bit deflection and tighter tolerances. This is especially true with materials like aluminum, and less ridgid machinesl though I find it also holds true for wood as well.

[microcarve]

That looks Great!



I make lots of machines, so I'll add a few thoughts.
Keeping in mind...as my disclaimer here...
...That I mainly build smaller machines these days. Cheaper,
easier to ship and little to go wrong...



The A-#1 thing of all that should very first be asked and considered
is....What do you want to make?

Next is What do you *Need* to make.

That helps decide what the design should/could be.

That helps decide the cost, materials, time to design/build, component
choices, etc....and chances of success.

Many want as large of a cutting area that will fit within a given
space. To "do it all". But a machine that's right for 2 x 4 signs
or cabinet doors may not mill PCBs anywhere near precisely enough...
unless it has a Very Serious amount of time and hard cash into it.


A lot of us have day jobs. It can be a problem to start running a loud,
large machine late at night...after the day finally winds down.
Noise alone can cause any progress to be delayed waiting for a weekend.

A smaller indoor machine can easily be enclosed and that quietens
it considerably...enough that a normal conversation can be heard
right outside the enclosure.

The smaller machine makes experimenting and learning the software
easier in that case. Software is where the learning curve begins.
Time for that is important.

There's one train of thought that goes...Buy Right-Buy Once.

The problem is, without a Really Good design...that is Proven to
work well...the chances of getting it 'Right' the first time are
verrrry Lowwww. Unless someone has Very Good mechanical skills, Plenty
of experience with a wide range of materials and knows exactly how
those materials are going to interact with each other....and has
access to some very expensive tools.

It can be useful and Very cost effective to make the inevitable design
mistakes on a cheaper experimental machine in many cases.

A smaller indoor machine can be cheaper and easier and the chances
of it working well are much improved. At least re-doing some part of it that
may be problematic aren't as much of a $$$ problem.

Aluminum expands and contracts about 2x what steel does. The bigger the
machine and the finer the component parts, the more temp changes alone
are likely going to be a problem at some point. Longer spans of aluminum
change size enough that it can make a bigger difference when compared to
a shorter/smaller span.

Flexibility needs to actually be considered and purposely designed in for
many designs. It's true. There Is a such thing as "too rigid".

When...Not 'if'...the sizes change, little rolling balls can dig
into the rail when their important oil film is broken. Binding and
galling and stalling happens then. Upgrading to more powerful drivers/motors
only makes that worse.

Mating surfaces make a huge difference. They need to be very well machined
in a lot of cases. Metal won't conform into square by just tightening bolts
a little more...it can actually get worse.

There are Tons of problems with the idea of building the 'do-it-all' machine
as a first project. Buying once can be a great idea...IF...someone knows
exactly what they're buying --and why they're buying it.



After building many machines, from many materials and combinations of materials,
I've come to view a DIY CNC machine as a 'specialty machine'.
Like a saw. There's a right one for the right job. One could make cabinets with
a chainsaw, but a table saw will do a much better job.

The do-it-all machine is certainly possible, but not too likely to work
without the tools, time, experience, and plenty of cash.

Knowing what really *needs* to be done with a machine is the very first
consideration IMHO. They All have their limits. It's my own opinion
that the machine should be built with a reasonable range of projects
in mind....but doing it all isn't likely to work out very well.

If someone needs to be "making things", the bolt
together kits can be a Very Good idea. If the goal is to "make a machine"...
and Especially so if it's a one-off design...then it can get far
more time consuming and expensive that it will seem. A proven, working
design plan is also a good idea in that case.

It's a Great! hobby, but there are tons of "gotchas" involved.

Homework is the #1 thing...next only to deciding what the machine designs
limitations will need to be. There will be limits.

I'll add, my observations come from the #1 question I get. "can you
make it bigger?"

Yep, I can make it bigger. But it gets exponentially more expensive,
It takes a lot more time, and it can get more flexible the more extended
it is. There's a cost point where it's the better idea to just buy
a commercial machine....and have something that can pay it's own way.

Homework. Decide the acceptable machine limits.

Maybe both of those are A-#1...


John

[Devastator]

That list looks great! I can think of a few to add. I've been guilty of a few on these lists already.

Being in too big of a hurry to start. "Go fever!"
This can cost you big time. You end up buying stuff that you can't use, make parts that won't work, then have to reorder and rebuild.

Being in too big of a hurry to finish.
Everybody wants to build a CNC in a week. You might be able to do it but will it meet your expectations? Timelines/deadlines can set you up for a mediocre machine that you will fight with for the next two years until you build a better one.

Short attention span.
If you are the type of personality that moves on to a new project every week without finishing any of them, a DIY CNC is not for you. Buy one already built instead.

Expecting a commercial machine capability from a DIY made from drawer slides and MDF cut with a hand saw.
Ain't gonna happen.

Setting too low of a budget.
Can you build a quality CNC for cheap? Sure, but you have to have resources and talent because you'll be making most of the critical components like leadscrew couplers, delrin AB nuts, soldering your driver board etc. You'll be replacing $ with time and labor...A lot of it. If you have a foundry, milling machine, lathe and know how to use them, no problem.

Trying to build too big of a machine as your first DIY CNC.
Better to learn how to build and run a CNC on a smaller machine. Cost is smaller, mistakes are smaller.

Believing you can build a wood gantry router to machine metal like a milling machine can.
Can some of the more rigid wood DIY CNCs mill metal? Sure, there are plenty of youtube videos showing it. But if you ask anyone who has a machine that can, it is nowhere as accurate or rigid as a milling machine and makes a huge mess because you can't run coolant and even spray from WD40 soaks into spoil boards and other wood parts. They only do it when they absolutely have to.

Expecting too much from a plan set that bases the design on hardware store materials.
These plan sets can be a valuable tool to give you the basics of CNC design. You are not going to go into commercial production with one, get over it. With some smart upgrades they can turn out some respectable quality as long as you work within their limitations.

Not caring about the speed of your machine.
A lot of people say this before and during the build. They do seem to care after the machine is done when they listen to the router running for days and watch the power meter spin. The cost of the multi-start screws can be recovered in electricity saved, spindle bearing longevity, less hearing loss, neighbor good will.

[epineh]

A couple from me...

Dont try to do anything too technical during the build very late at night after working 12 or more hours at your day job, simple mistakes happen easily enough as it is, no need to tempt fate.

If you are running a job that requires a toolchange before running a new section of code, make sure the correct code is loaded after the toolchange, running the wrong code is really messy. Wouldn't hurt to double check the next tool is correct and the Z offset is done before pulling the trigger again.

Cheers.

Russell.

[robe_uk]

What lists! And I think am guilty of nearly all points, I tend to rush in without proper planning, end up making mistakes which can dishearten and slow/stall a build. So my advice would be do some research and copy working build on this site, no need to reinvent the wheel. Let others make the mistakes lol.
But in saying that building was part of the fun for me and the router only gets light use for any small projects I think of, really need to get it earning its keep.

Cheers rob

[louieatienza]

Some excellent ones I missed! Just wanted to add my thoughts on some...

As to not caring about the speed of your machine, I would guesstimate this lasts for about two days. 35ipm sounds pretty fast until you watch it going in a straight line. It might be OK if you're building a mill with a low speed, high torque spindle. For wood this can cause burning, and premature wear on bits.

With believing you can build a wood gantry router to machine metal like a milling machine can I'm sure most every machine on this forum can cut metal to some capacity. I actually cut aluminum on a regular basis for a few clients. Whether you'd want to do it every day as part of production or semi-production, and rely on it, is what may be in question. Thankfully my parts need not be aerospace tolerances, and I change my spoilboard very frequently. They build cars now out of aluminum space frames and monocoque frames. If these machine builders thought they could make a successfull VMC out of aluminum or even steel, don't you think it would have been done? A wood router is realy not designed for repeated cutting of metal, unless you consider the router disposable. A metalworking spindle would be far better, but again, a lot depends what ou mate it to.

On running a job that requires a toolchange before running a new section of code, I prefer to have a different job set up for each tool change. This prevents a lot of misatakes, and makes it easier for me to re-run an operation without fuss. This is also handy for parts that might have the same external feature but different internal features; you won't have to reprogram toolpaths, and I hate doing things twice...

One I forgot, decide what you want your machine to do beforehand. I can understand the allure of owning a CNC. It is actually fun to watchan idea go from computer screen to finished part, as if some mystical power is moving the machine. The thing is, if there is no purpose to your machine, you may have an expensive toy sitting in the corner of your workshop. It's like owning a small boat; the cost of ownership of a CNC is not trivial; maintenance need to be done, software gets updated, bits need to be replaced, metal rusts and corrodes and needs to be addressed, bearing need lubrication, sliding surfaces need to be cleaned, spoilboards need to be resurfaced and replaced, fixtures and other hold downs need to be bought... I'm sure there are some tinkers, who use their CNC just to experiment and humor themselves, and that's fine; but realize it comes at a cost!

Maybe related to the last point, is the "Look what I can do with my machine!" crowd. This is probably more of a rant than a troubleshooting topic. I do love watching the tech demos of the big name machine makers. Watching a Matsuura Maxia machine an engine block out of a solid billet of aluminum, and slinging said block around like it weighed 2 pounds, is pretty impressive. While it's great to see the capabilities of some of the better builds here, at least some insight as to the machining parameters would be helpful to those watching. It wasn't too long ago, maybe a couple years, when I came here looking for info on cutting aluminum, and I got the feeling that it was some weird closely guarded secret. I had done extensive testing on my own machine and had found parameter that worked for me, and shared them both here an on YouTube. I don't ever recall seeing any information on single-edge spiral-"O" flute bits for aluminum when doing research into aluminum routing, but I stumbled upon them at ToolsToday.com and they work extremely well for the typical higher-rpm spindles of the typical DIY machine. Heck, they even advertise here now, and there are many here that use them successfully. Point is, while you may have your own "trade secrets," as a member of a community it would be great if more ideas can be shared, as to benefit the whole forum.

[louieatienza]

Yet another rant possibly, but relaed to my last point...

If you want others to participate in your build thread, it may be helpful to reciprocate. There are numerous builds, where a machine is being built, and there are not many posts from other members. Usually somewhere along the build, the builder will post something like, "Is nobody watching this?" Well, a quick look at the page views on the main page would answer teh builder's question. I do enjoy watching others work, as well as others observing my work and commenting. This is an online CNC community, and part of being a member of a community is interacting with others. There are a few builds here that suffer this fate of very little comments from others, as if the build was some sort of side show in a circus. Criticism has to be received with the same enthusiasm as praise. And there really is no one here reinventing the wheel - all "new" ideas seen here has been seen before, somewhere.

[br1]

All very good points.

[JerryBurks]

Agree with pretty much everything said here...
Something that catches my eye quite often with new design proposals here:

Use the Area Moment of Inertia ! Bending of plates and beams is a concept not well understood by some non-engineers. There are many design proposals consisting of slender plates for critical parts without gussets, tube reinforcements, torsion boxes and the like. However, if only a simple plate is used e.g. for a tall gantry upright it needs to be very massive for good stiffness. A simple design change can often result in a much better machine with lower mass and lower cost.

A machine must be HEAVY to suppress vibrations. This is not necessarily the case (it may or may not help). Generally a more massive machine is probably stiffer (moving resonance frequencies up) but obviously have more mass (move resonance frequencies down). Depending on the spindle speed and number of flutes either one can be better. More influence has the material damping property with steel and aluminum pretty poor (there is a reason bells are made of metal). Cast iron, concrete and wood have better damping properties but may have other design disadvantages. Overall, such modal resonance analysis (nice explanation for rotating machinery here) is way beyond the hobbyist abilities and it is hard to give clear recipes. I don't see a choice but design along guidelines proven by experience or just take a risk for a new design or material idea. But it will be hard to objectively prove an advantage of such a new idea.

[aarongough]

Great thread!

I think that speeds and feeds, and how they are derived, is a really important thing for new people to understand, possibly even before they set out their design goals. It's easy to think that 35IPM in a CNC router is blazing fast until you start thinking about the spindle speed of a typical wood router and the chip-loads that entails.

So, let's try this:

Feedrate (Feed):
How far the machine moves through the material in a given amount of time. Feedrates are usually defined in either 'inches per minute' (IPM) or 'meters per minute' (MPM).

Spindle Speed (Speed):
How many times the spindle of the machine rotates in a given period of time, usually defined using 'revolutions per minute' (RPM).

Chip-load:
The chip-load is how much material is removed by each flute or tooth of the cutter per revolution. This is usually defined in thousandths of an inch, or in mm.

If the chip-load is too low then the tool is unable to bite into the material being cut, this results in the tool rubbing against the material instead. Each time the tool rubs it generates heat through friction. This heat stays in the tool and makes it wear out faster. It may also burn the wood, or melt the aluminum or plastic that you're cutting. Chip-loads that are too high will either cause the cutting edges of the cutter to chip, or the cutter will just break in half.

As a general rule chip-loads in any material need to be at least 0.005". This only applies for cutters of at least 1/8" diameter. Smaller cutters will need smaller chip-loads. The maximum chip-load depends on the tool, as well as the machine you're using because larger chip-loads generate larger forces. Usually the maximum chip-load for a given machine/tool is determined through experimentation or by using the manufacturers data-sheets as a reference.

Calculating Feeds and Speeds:
For most people building a CNC router, the lowest speed of their router is the main determining factor for their Feeds and Speeds.

Feedrate (IPM) = Spindle Speed (RPM) x Desired chipload (Inches) x Number of flutes in the cutter

The spindle in my router has a minimum speed of 16,000RPM. Therefore:

Spindle speed (16,000RPM) x Chipload (0.005") x Flutes (2) = 160 Inches per minute.

If my machine cannot achieve a cutting speed of at least 160IPM then I'm going to be burning through tooling at a rate far higher than necessary.

Given that most home-built machines tend not to be terribly rigid, we compensate by taking only a small depth of cut, while still maintaining the proper spindle speed and feedrate. If we were to upgrade to a more rigid machine with the same spindle, then our jobs would get done faster because we would be taking a deeper cut at the same speed and feed.

Hope this makes sense, and that it helps!

[Al_The_Man]

I don't recall seeing a thread dedicated to problems arising before, during, and after construction of a DIY CNC router, and thought it might be of interest to others, as well as open up discussion on certain topics:

Lack of attention payed to the Electrical and Control side of the Machine: Just an observation from someone in the Control side of machine building.
It seems that often a great deal of attention is paid to the mechanics of the machine itself, but when it comes to using conventional methods of enclosure, panel wiring and layout, there is often alot left to be desired.
Some do take pride in a neat layout, but with many I have seen here, it is a good job the enclosure door can be closed and it sight unseen!
I realize that most do not have any kind a background in this area, but one only has to look at existing commercial machines in order to get an idea for accepted layout standards, also there is a booklet on the whole subject, NFPA79, Electrical Standards for Industrial Control.
Proper layout also helps remove the possibility of transient triggering of inputs etc.
Al.

[pirate323i]

Great thread!
I am definitely guilty of a few of these...

[louieatienza]

Lack of attention payed to the Electrical and Control side of the Machine: Just an observation from someone in the Control side of machine building.
It seems that often a great deal of attention is paid to the mechanics of the machine itself, but when it comes to using conventional methods of enclosure, panel wiring and layout, there is often alot left to be desired.
Some do take pride in a neat layout, but with many I have seen here, it is a good job the enclosure door can be closed and it sight unseen!
I realize that most do not have any kind a background in this area, but one only has to look at existing commercial machines in order to get an idea for accepted layout standards, also there is a booklet on the whole subject, NFPA79, Electrical Standards for Industrial Control.
Proper layout also helps remove the possibility of transient triggering of inputs etc.
Al.

The nice thinkg about the G540 is that my control box has less wires than the fingers on my two hands...

This guy has a nice setup (and probably one of the best DIY machines I've seen.... ever:
[ame=http://www.youtube.com/watch?v=fIVL83AwXrE]Homemade cnc router - YouTube[/ame]

[Bob La Londe]

would be helpful to those watching. It wasn't too long ago, maybe a couple years, when I came here looking for info on cutting aluminum, and I got the feeling that it was some weird closely guarded secret. I had done extensive testing on my own machine and had found parameter that worked for me, and shared them both here an on YouTube. I don't ever recall seeing any information on single-edge spiral-"O" flute bits for aluminum when doing research into aluminum routing, but I stumbled upon them at ToolsToday.com and they work extremely well for the typical higher-rpm spindles of the typical DIY machine. Heck, they even advertise here now, and there are many here that use them successfully. Point is, while you may have your own "trade secrets," as a member of a community it would be great if more ideas can be shared, as to benefit the whole forum.

I think there are some very knowledgable machinists who don't understand high speed machining at all. I ran into huge walls of frustration trying to figure out how to get decent material removal rates with tiny cutters in aluminum myself. In one group somebody who I thought was a machinist icon told me, "Bob, You may be the only expert here in what you are trying to do." That floored me. I've been playing with machining for a few years now. Primarly detail 3D cutting in aluminum, and I do not consider myself an "expert" in any part of it.

This brings me to my own newbie comment. Its one that is not solveable. Thinking there is a formula or standard for everything. There is no magic formula for everything, and there is no perfect machine. There are a lot of good guidelines and starting points, but every machine is its own little microcosm that needs personal understanding and experience. Especially hobby level and DIY build machines. Some things transcend individual machines, and some things only work on your personal work of art.

[Devastator]

I think there are some very knowledgable machinists who don't understand high speed machining at all. I ran into huge walls of frustration trying to figure out how to get decent material removal rates with tiny cutters in aluminum myself.

Good point. I recently had this problem trying to find out how to machine 3003 aluminum with 1/8" cutters on my machine. I was melting material and breaking bits left and right. I got lots of advice from experts and went through a lot of bits and material because of it. Then I went against all advice that I was given and machined it at feeds and speeds recommended for steel. Slow as hell, but clean. Not sure what the cutter life will be but a heck of a lot longer than breaking them in the first two seconds of cutting.

Even very experienced machinists won't touch 3003, most told me to switch to another grade of aluminum. I can't because it is sheet that has to be easily formable.

[louieatienza]

Good point. I recently had this problem trying to find out how to machine 3003 aluminum with 1/8" cutters on my machine. I was melting material and breaking bits left and right. I got lots of advice from experts and went through a lot of bits and material because of it. Then I went against all advice that I was given and machined it at feeds and speeds recommended for steel. Slow as hell, but clean. Not sure what the cutter life will be but a heck of a lot longer than breaking them in the first two seconds of cutting.

Even very experienced machinists won't touch 3003, most told me to switch to another grade of aluminum. I can't because it is sheet that has to be easily formable.

Onsrud actually makes a bit for this, a low helix single edge spiral-"O" flute that's ZrN coated... though the smallest size they offer is 3/16". I personally try to use 7000 aluminum if possible.

[dbsharp]

I have never had good results with a single flute end mill, they seem to deflect too much. Even with a very short one.

My best results in aluminum is with a 3 flute and a strong mist blast to clear chips running hsm toolpath. 2 flute end mills seem to be a little less likely to clog up esp when slotting.

[Devastator]

Onsrud actually makes a bit for this, a low helix single edge spiral-"O" flute that's ZrN coated... though the smallest size they offer is 3/16". I personally try to use 7000 aluminum if possible.

I considered trying that exact bit but my part has a lot of holes that are smaller than 3/16".

[Devastator]

My best results in aluminum is with a 3 flute and a strong mist blast to clear chips running hsm toolpath. 2 flute end mills seem to be a little less likely to clog up esp when slotting.

Seems I'm on a similar path then. I'm using a Destiny Viper three flute with Stealth coating with "pretty good" results. 75 IPM @ 18,000 RPM. Very low chip load, but if I increase it I get chip welding. I've also found my DOC has to be 1/4 of what I take in 6061 or it balls up on the bit. Once it does that, you're done. Bit breaks, piece is ruined, game over. 3003 is a PITA. I may try backing down the RPM but I'm scared of breaking more bits.

[dbsharp]

the key to avoiding chip rewelding is to get them chips outta there! I use 50 psi with my fog buster style mister and it really blows the chips out of there, most people don't use much pressure, like 10 psi or so. Also I try to avoid slotting like its the plague.