A Milestone

[Joe Lavery]

Just a short message to all,

Because of our advanced ages, my wife and I started self isolation about 10 days ago. This had given me more time to look to things I've not had time for in the past.

One of these concerns my Small CNC machine, which I've never been able to cut aluminium with. I either managed to snap the carbide cutter, or made a horrendous mess of the part I was cutting. Making it more sensible to cut it by hand on my band saw. Well 2 days ago I saw a post on one of the CNC forums by someone who has a similar machine to mine, showing him successfully cutting a 5mm thick aluminium plate.
I seems I was to aggressive with both the speed and feed of the cut. So I followed his example and dropped my router speed to 10,000 RPM and used a feed rate of 300mm per Min. this was much slower (and faster) than I'd ever contemplated before. My theory being faster router, slow feed equals better cut.
But the setting that made the most difference was the depth of cut. He suggested 0.1 mm which for 5mm makes 50 cuts. I settles for 0.2mm which was still 25 cuts but it worked like a charm. I don't mind the time element, because both the cutter and the router were not even warm when it completed the job; (which incidentally was a 737 flap gate). I did squirt the occasional drop of WD40 while it was cutting.
I've only posted this because it shows if you do the research someone will have an answer, which is why forums like this are so helpful. I know many of you out there with a lot more knowledge and expertise will say these settings are obvious, but I thought over the 4 years I've had this machine that I'd tried every combination; it seems I hadn't!. Although I've cut everything from 25mm Birch plywood to various thicknesses of acrylic, aluminium always had me beat; not any more!!

Don't look too close at the image, it was an old piece of aluminium so I had to clean it up with some emery cloth, the camera highlights the scratches.

In these somewhat dangerous times, particularly for people of a certain age and with less than perfect health, staying at home is a sensible precaution.
I sincerely hope you and your families all remain safe in the coming months, and perhaps put your grey matter to solving a similar puzzle that has perhaps so far eluded you.

Best regards all
Joe

[sagrada737]

Hi Joe,

Nice job on that TQ Flaps part.   Yes...  CNC can be a significant challenge at times.  With most all machining operations, setup can be time consuming, and can have an effect machining the work piece.

For years, I have been using theTormach PCNC1100, which is light duty CNC milling machine.  I also use their CNC Turret lathe.  I am definitely not an expert at CNC machining, but I do understand that what is critical to any machining operations, are the Speeds & Feeds.  In addition, to be factored into the machining equation are the type of cutter being used, clearing of chips, and cooling/cutting fluid.

With respect to Speeds & Feeds...   Regardless the type of machining center you have (hobby or industrial), you need to adhere to proper Speeds & Feeds settings.  This involves (but not limited to) the type of cutter you are using, the depth of cut, and the amount of tool engagement. 

The best thing for you to do is to use a Speeds and Feeds Calculator.   Here is a link to one by LittleMachines.  If this calculator does not match the specs on your CNC machine, you can find other such S&Fs calculators online...

https://littlemachineshop.com/mobile/speeds_feeds.php

In all this, you can't guess at the Speeds & Feeds settings.  That usually results in poor results at best.   When you have your Speeds and Feeds setup correctly for the milling operation you want to do, then you can expect better cutting performance, longer tool life -- and overall a better finished machining operation.

Safety is also a concern, as improper Speeds & Feeds can result in machine and/or tool failures.   ALWAYS WEAR EYE PROTECTION!!!  It's also a good idea to count your fingers before machining, and after machining... Even small CNC machines can be dangerous if not setup and run properly.   Enough said...

What CAD/CAM software are you using?

Mike

[Joe Lavery]

Hi Mike,

Yes I realised some time ago the importance of all these settings, unfortunately there are equally many conflicting "advisors". So I resorted to the admittedly imperfect method of trial and error. 

I'm afraid my old head couldn't cope with all these calculations. My strength is in CAD and 3D design, which I used to do for a living, but now it's great for 3D printing and making stuff for FS.

My CNC is an American made Zenbot 600 x 400 which originally had a Dremel 3000 as the router. I never used that but changed it immediately for a Kress 1050-FME1, which is a semi professional unit made in Germany.

I use Mach3 software that came with the machine, which was second hand but actually never used.
Drawings are done in Artcam, AutoCAD or Sketchup, depending on the item. My AutoCAD is an old version I used to have in work, but recently I've been working with NanoCAD 64 which is a Russian made AutoCAD clone. It has a free version and if you've used AutoCAD will be easy to change over to.

Thanks for the links I'll have a look later and see if I can use the calculator.   

Joe.

[sagrada737]

Hi Joe,

Glad to hear you have an extensive background in CAD, which bodes well for your CNC efforts and any 3D printing you might do.   As you know, designing for subtractive machining vs. the Additive process of 3D printing.

I hear you on the "depth of cut" solution.   When nothing else seems to work, taking a lighter cut sometimes gets you through the machining operation.   The disadvantage of this is that it can lead to premature tool wear at the tips of your cutting tool.  Even Carbide tools can take a hit in this manner.

Properly "loaded", your cutting tool will cut very efficiently at greater depths of cut, assuming you have the correct Speed & Feed.

Using a good cutting fluid can make a big difference as well.   I use a Cool-Mist system with Dura-Kut 4010 cutting fluid.  The spray system is especially good for "evacuating chips" as well as keeping your tool cool.   This might be very useful for the high RPMs you are using.  Of course, spray misting and cooling fluid can be a bit messy in your machining area, but unlike "Flood Cooling", the spray-mist system uses very little cutting fluid.

By the way...   What is your favorite 3D printer filament for dimensional stability?

Mike

[Joe Lavery]

Hi Mike,

I think my main problem is the rigidity of my machine, it's made mainly from Delrin, so not as stiff as metal and I think that's why shallow cuts work. However I'm sure given the optimum settings it could cut a bit deeper.
Having said that the cutters I use are pretty cheap, I've tried cutters costing 10 times as much with no appreciable improvement, of course the settings once again may be the culprit. 

I did buy a spray mister but my main base plate and spoil boards are Birch ply and MDF respectively which don't like liquid. However I did get some success with alcohol, (not drinking it you understand).

I mainly use PLA, although I occasionally use PETG if I want a stronger part. But to be honest I find PLA is fine for most things; of course it remains to be seen if PLA has a long life once printed. It does deteriorate over time if left exposed, whereas PETG does not.
I have never tried any of the stronger filaments, I have an Ender 3 and a Elegoo Mars resin printer; which have both been excellent value, turning out very clean and detailed prints. If I need a strong part I print at 100% fill.

Joe.

[sagrada737]

Hi Joe,

I now better understand your CNC setup.   Considering the "heft" of your milling machine, it is best if you do take smaller cuts.  Also, if it's possible, try to further reduce the Spindle Speed to see if you can find a better setting for milling aluminum.

Regarding 3D printing...   I too like PLA.   It is very easy to print, and is good for making various kinds of parts.  I would suggest that you give PLA-CarbonFiber a try.  I use a PLA Carbon Fiber filament made by SunTop.  I print it at 210C nozzle temp, with a Bed temp of 55C.  It is structurally stronger and dimensionally more stable.  It also can be printed fairly fast.  Give it a try...  I think you will like it.

You also might try switching to a 0.6mm nozzle.

The Creality Endor 3 is a nice low cost 3D printer.  You have to carefully calibrate and monitor the nozzle to Bed gap, but other than that, it is fairly reliable.  I currently use the Creality 10S Pro.   I very much like the auto Bed Calibration Profile feature, which takes account Bed surface variations.   I also have found that using a "mirror tile" for my Bed surface plate works very well, and provides excellent Bed Adhesion for most filament materials.   For PETG and ABS, I use a Mirror Tile with a Kapton surface.

Mike

[Joe Lavery]

Hi Mike,

If I want nice clean prints I print at a layer height of 1.2mm. I don't have any problem with adhesion because I bought a product called Printbite about two years ago and have never had a failed print since. It's a brilliant product that grips the part like a vice, perhaps the only drawback is you have to wait until it cools to lift it off. It's amazing how it seems almost welded to the bed, then once it has cooled it releases automatically.

I added this sheet onto a Mirror tile, which is slightly smaller than my bed at 200 x 200 but it's never been a problem because I don't print large models. I run with 210 nozzle heat and 65 for the bed with a small brim to clean the nozzle at the start of each print.

I have considered changing the main board and adding a bed levelling device, but as it works very well as it is I've never got round to it. To be honest I rarely have to change the bed level, I get consistently smooth base surfaces, almost like a solid sheet. If I start to see the base layers more prominently I tweak the adjusters a bit; that's generally all that's needed.

Of course I may just be lucky to have a stable machine, a friend of mine bought one just after I did and his prints are nothing like mine. In fact I've sent him my settings and tried to talk him through the setup but with virtually no improvement. He's not local to me or t would have been interesting to see if there are any mechanical issues.

I might give the Carbon Fibre a go, but when I bought the Ender I also bought a lot of filament, currently standing at 14 x 2Kg rolls. I bought far too many different colours, and of course the wife and family chipped in as well.

Still at the moment I'm working on the 737 Deck, trying to get it back into service after 4 years. I've nearly finished the shell, so with this enforced lockdown in the UK I may even get if flying again.

Joe.

[blueskydriver]

Hey Joe,

Glad to hear you're moving along with all of this. Would you believe I still have the CNC that Scott sold me years ago and haven't used it yet?!

Eventually, I will get there, but in the mean time, how much will you charge to make the same aluminum Flap Gate for the 737?

Also, got a challenge for you. Can you design/make a 3D circuit breaker light fixture that goes (1) on each side of the side walls? If you look at those panorama links I posted earlier you'll see it.

Pretty much a tube shape with a slit for the light too shine through. A small 12v bulb or led setup would work perfect....

Kind Regards,

John

[Joe Lavery]

Hey John,

You're pretty prolific in this forum, you should join the CNC forum https://www.cnczone.com/forums/
You will find all you need to get your machine up and running there, it's a massive forum and full of very knowledgable people.

Regarding the flap gate, of course I could make you one, but as you've found out the postage from the UK is prohibitive. Another issue is that this part was made to fit my own design throttle, so it may not fit yours. If you have a exact CAD drawing then I can make it, but I'll find out the cost of postage for you first.

I've had a look at the Panoramas but can't see the Circuit breaker light fitting you're referring to.

I've attached an image captured from one of these Panoramas, it's being used to hang headphones on, is this what you mean?

Cheers
Joe.

[blueskydriver]

Hi Joe,

Thank you for the CNC link, I will definitely join.

As for the flap gate, I need it sized as the real one is for the B737 style gate. Mine is a B727 gate wise, but same in the actual size. Maybe, I can pull mine off and trace it out. Shipping costs no worries.

Regarding the CB Panel lights, check these pics out. Also, another item you could do is the sidewall vents shown.

John

[blueskydriver]

More pics...

[Joe Lavery]

Something like this you mean?

There are two types, the ones that I've drawn and the ones that don't have the bezel around the glass.
The second type are easier to make because they make a natural support for the glass or perspex face.

Joe.

[jackpilot]

Nope , these are lamps lighting the CB panels. I think John refers to the vent grills.
Actually you can find this (pretty close) in hardware stores

https://www.rona.ca/en/air-intake-hood

[Joe Lavery]

Hi Jack,

Did you read his post and see the images he sent me, it's the CB lights he asked about.
Which if you look are the ones in the images attached. The image with the two lights are I believe the ones you're talking about.

Joe.

[blueskydriver]

Hey Guys,

Thank you both for providing what I am looking for. Joe, the CB Panel lights (2nd version) you have drawn with the bezel is perfect. Do you have a .stl for it yet and wouldn't mind sharing?

As for the other light sets that attach to side wall (the ones in the pic I reattached), I already have those. However, it would be awesome too make up a 3D print version of them. Wouldn't really need the off/dim/bright function, just an off/on would be enough.

Hey Jack, the vent you posted the link for is perfect. Also, sorry if I caused any confusion with the lights previously, sometimes things are not labeled so easily with Boeing.

Kind Regards,

John

[Joe Lavery]

Hey John,

The Grimes light has already been done by our friend from 737DIYSIM. it's on Thingyverse. The one with the red cap. So I don't want to reinvent the wheel. 

https://www.thingiverse.com/thing:3535007

Regarding the other one, I've been looking to see the best way to print it. I might have to split it in half, Then I'll create the stl files and you're welcome to a copy. I will add it to Thingyverse as well.

Joe.

[Joe Lavery]

Just an update to the Grimes light saga.
I've printed it in PLA and although I used the size as documented, I didn't realise how small it is.

It needs some careful supports to get it printed, because the tube feeding into it extends beyond the main housing. I also added a few small supports under the recess to take the obscure lens.
Even though I printed it at a layer height of .12mm the surface clearly shows the layers. If I was going to use it I would paint it with high build filler paint, with a final topcoat of semi matt black.
Perhaps adding the lettering laser etched onto thin two colour acrylic.

(Incidentally I printed it face down on the bed.)

Anyway it will be on Thingiverse shortly for whoever wants to print their own.

Joe.

[blueskydriver]

Hey Joe,

AWESOME! Thank you for doing this.

Can I ask what program you use for the slicer? I have Simplfy3D.

Basically, if you by chance have the same, will you share the S3D file where you did all the supports?

Just thinking the best work is already done by you, so no need for me to do it again and likely a bad job at that...lol.

Thanks again, and please keep doing such great work for our community...

John

[Joe Lavery]

Hi John,

It's not a problem, it's a fairly simple model.

I also use S3D but I sadly don't have the factory files, I didn't save them. To be honest I only printed it to see how it turned out. However I do have the G-CODE files that you can use to print them directly. I also have the ST files which are now on Thingiverse.

https://www.thingiverse.com/thing:4265399

There are two options on Thingiverse, one where I split the main body in two, which I haven't printed it also comes with a separate Bezel. The version in my image is printed face down in one piece. I will add all this to a zip file for you, including the G-CODE files. You can also try the split version if you like, let me know how it prints if you do!

If you want to see the supports I added you can double click on the G-CODE file and it will load into S3D. You won't be able to edit it but at least you can see what I did.

My settings are:

Layer Height .1200
Top Solid Layers 4
Bottom Solid 3
Outline Shells 3
Fill 100%
Temperature Extruder 210
Temperature Bed 65

First Layer Height 150%
First Layer Width 150%
First Layer Speed 40%

Hope this is useful.
Joe.

 

[kattz]

This is sweet.  BTW, to get rid of the lines, you can use a primer/filler, or what I use, which is acetone vapor smoothing.

Easy - get a 2 gallon chemical-resistant bucket and lid, (from Lowe's or Home Depot or equiv), and an empty pint paint can from someplace like Sherwin Williams - you can also get a 1 gallon can from them instead of the bucket.

Get a can of acetone.

Set the pint can in the bucket, set your part to be smoothed on the pint can.

Pour some acetone on a shop rag or even a paper towel, and place the rag etc. in the bottom of the bucket.

QUICKLY put the lid on the bucket.  Wait several minutes, and then open the bucket. Take out the rag etc.

Check your part and most of the lines will be gone.

Lather, rinse, repeat as desired.

You can also use a little acetone on a paper towel and gently rub the part and the lines will disappear.  Works better for ABS than PLA.  I only print in ABS.  Rigidity.

Your mileage may vary.  Tax, tag, and title, destination fees not included.  Some assembly required.  See store for details.

Kev