Author Topic: Desktop CNC  (Read 1508 times)

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Offline rx8pilot

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Re: Desktop CNC
« Reply #25 on: January 14, 2018, 04:23:28 PM »
I had no idea OSH Park even had FR408.

The demo video looks pretty good, but the machine looks devastatingly weak to me. Clearly they are making things with it, but I wonder how many tried it took. I saw a video where an end user seemed to have some success, but only after leveling the table which was far from flat on arrival. The Carbide looks better.

Wonder what happened to the Cirqoid product. It looked way better mechanically.

Also, Prometheus looks interesting.
https://www.zippyrobotics.com/


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Offline blueskull

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Re: Desktop CNC
« Reply #26 on: January 14, 2018, 04:34:25 PM »
I had no idea OSH Park even had FR408.

The demo video looks pretty good, but the machine looks devastatingly weak to me. Clearly they are making things with it, but I wonder how many tried it took. I saw a video where an end user seemed to have some success, but only after leveling the table which was far from flat on arrival. The Carbide looks better.

Wonder what happened to the Cirqoid product. It looked way better mechanically.

Also, Prometheus looks interesting.
https://www.zippyrobotics.com/



OSHPark uses FR408 for 4L boards.

I just sent the Zippy Robotics guy an email, and asking him whether the machine can also mill aluminum. Fingers crossed. Thank you for this recommendation.
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Offline mrpackethead

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Re: Desktop CNC
« Reply #27 on: January 14, 2018, 04:47:34 PM »
Dont' forget the cost of tools, clamps, measuring equipment..  You'd be suprized how fast that adds up to at least as much as the machinery.. 

Btw,  a router on a gantry is not a Mill, and vice versa.     I have both a CNC mill and and cnc router, and they both have their place.    I make die sets in aluminum for injection moudling on my mill,  and i cut out wood and plastic on my router.
 

Offline blueskull

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Re: Desktop CNC
« Reply #28 on: January 14, 2018, 04:55:25 PM »
Dont' forget the cost of tools, clamps, measuring equipment..  You'd be suprized how fast that adds up to at least as much as the machinery.. 

I don't mind spending on material or time, just don't want to spend too much on equipment. That means I'm okay with using machinable wax or whatever consumables to hold down the stock.

I don't know what kind of measuring gears I need, but I do have a micrometer and a caliper, both from Mitsutoyo.

I need a band saw to cut long stock into pieces, but I can also just order pre-cut from local hardware. My local hardware store offers free cutting and bending as long as the pattern is very simple.

Btw,  a router on a gantry is not a Mill, and vice versa.     I have both a CNC mill and and cnc router, and they both have their place.    I make die sets in aluminum for injection moudling on my mill,  and i cut out wood and plastic on my router.

I'm aware of that, and I don't need a a CNC router besides routing PCB shapes. For aluminum works, I only need rectangular outline so I can just use a manual power mill.

My goal is to have the smallest ME+EE lab that I can pack and ship to anywhere in the world with my for less than $1000 of freight, or even in a large luggage.
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Offline blueskull

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Re: Desktop CNC
« Reply #29 on: January 14, 2018, 05:14:17 PM »
I just sent the Zippy Robotics guy an email, and asking him whether the machine can also mill aluminum. Fingers crossed. Thank you for this recommendation.

Wow, they respond fast! Unfortunately the answer is negative. It's not designed to mill solid metal and is not stiff enough to eat into metal. If I insist, it will take many, many passes of very thin depth to do it.

Also, it doesn't have such firmware to cut solid metal, and that feature will be added after stencil milling feature, so I guess that won't happen very soon.
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Offline rx8pilot

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Re: Desktop CNC
« Reply #30 on: January 14, 2018, 05:23:20 PM »
I just sent the Zippy Robotics guy an email, and asking him whether the machine can also mill aluminum. Fingers crossed. Thank you for this recommendation.

Wow, they respond fast! Unfortunately the answer is negative. It's not designed to mill solid metal and is not stiff enough to eat into metal. If I insist, it will take many, many passes of very thin depth to do it.

Also, it doesn't have such firmware to cut solid metal, and that feature will be added after stencil milling feature, so I guess that won't happen very soon.

I think you will find this to be true with most of them. It really is a different task.
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Offline Koen

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Re: Desktop CNC
« Reply #31 on: January 14, 2018, 08:03:24 PM »
Example above isn't so much milling soft metals as it is grinding soft metals. You don't make chips, you make powder. It's hard on the endmills, they have to be replaced often. Also, heat won't be escaping by the chips as should be and thus, both the endmill and the piece will heat up plenty, leading to problems.

If I were you, I'd put a classified looking for someone owning a nice mill in a similar semi-pro setting. And ask them a price for machine time. You provide a nearly-done file and the material stock. They mill with a little profit. Maybe a "FabLab" would do. It's not very developed here so I wouldn't know.

Or you know, China. Nowadays, I send a step file, pay ~300 USD, wait a week and receive 4 samples by express courier. It's somewhat stupid of me I agree but I don't have much time anymore and it's much more convenient than sourcing the material myself, sourcing the endmills, any specialized tooling, preparing the machine, making a mistake or another and so-on. The mill now only serves big/heavy/expensive projects like making other machines.
« Last Edit: January 14, 2018, 08:06:16 PM by Koen »
 

Offline Magnum

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Re: Desktop CNC
« Reply #32 on: January 14, 2018, 09:58:20 PM »
Here is a (german again) machine that is good for PCBs and can handle aluminium:
https://www.sorotec.de/shop/Portalfraesmaschine-CL-Line-0403.html
It has ball screws, linear rails and weights around 50kg for 300x400mm travel. The price is without electronics and stepper motors, that is another 1.500 EUR. So altogether EUR 3.800 with VAT, EUR 3.200 without VAT.
Here some videos of building these machines. You can see how rigid the construction is:



And here cutting aluminium:


Even iron:


With such a machine you have the accuracy you need. Something similar should be available in the US, just check the construction first.
 

Online mtdoc

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Re: Desktop CNC
« Reply #33 on: January 15, 2018, 05:51:27 AM »

I need a band saw to cut long stock into pieces, but I can also just order pre-cut from local hardware. My local hardware store offers free cutting and bending as long as the pattern is very simple.


For an amazingly capable, inexpensive and portable band saw solution I can highly recommend the following.

1. Bauer handheld 10 amp variable speed bandsaw. Yes , it's from Harbor Freight.  But this is one of their hidden gems. Read the reviews. With their ubiquitous 20% off coupons you can get it for $80. It comes in a nice case which is perfect for your portability concerns.

2. Swag portaband table. These things are awesome. They are very well made and can be broken down to a small package.

Optional - Add a good miter gauge (I am using this one) for precise cuts and a cheap foot switch.

I've been using this setup to cut stock and it works very well.  It's also nice to have the option of using the saw hand held for removing stock from large pieces (or from the junkyard, etc).



« Last Edit: January 15, 2018, 06:53:18 AM by mtdoc »
 
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Offline rx8pilot

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Re: Desktop CNC
« Reply #34 on: January 15, 2018, 06:13:30 AM »
For an amazingly capable, inexpensive and portable band saw solution I can highly recommend the following.

That looks AWESOME for my tiny shop.....thanks!
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Online mtdoc

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Re: Desktop CNC
« Reply #35 on: January 15, 2018, 06:54:44 AM »
For an amazingly capable, inexpensive and portable band saw solution I can highly recommend the following.

That looks AWESOME for my tiny shop.....thanks!

I added the link to the Swag table. I bought mine from Amazon but it turns out it is cheaper ($129) directly from Swag. :palm:
Version 3.0 is the one compatible with the Bauer band saw.
« Last Edit: January 15, 2018, 06:56:23 AM by mtdoc »
 

Offline cstratton

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Re: Desktop CNC
« Reply #36 on: January 15, 2018, 07:28:22 AM »
Given the portable tool heritage that looks like it uses a brushed universal motor.

It may give easy speed control as a result, but beware that such tools are far noisier than conventional fixed machinery powered by induction motors.  A bandsaw should be nearly silent especially when it's not cutting anything resonant.

Doesn't mean it's a bad thing to own, just be aware of the tradeoffs.

Also, don't buy a bandsaw until you've used a proper hacksaw with the right blade in a tubular steel frame - while not a bandsaw, it's a much more pleasant experience than the usual stamped frame hardware store variety.  And quite cheap too.
« Last Edit: January 15, 2018, 07:31:48 AM by cstratton »
 

Online mtdoc

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Re: Desktop CNC
« Reply #37 on: January 15, 2018, 07:38:09 AM »
Given the portable tool heritage that looks like it uses a brushed universal motor.

It may give easy speed control as a result, but beware that such tools are far noisier than conventional fixed machinery powered by induction motors.  A bandsaw should be nearly silent especially when it's not cutting anything resonant.

Doesn't mean it's a bad thing to own, just be aware of the tradeoffs.

There are always trade offs.

Yes it's a brushed motor. It even comes with a set of replacement brushes.

But the speed control is essential IMO and it is not very loud.  A trade off I'll take any day.

Quote
Also, don't buy a bandsaw until you've used a proper hacksaw with the right blade in a tubular steel frame - while not a bandsaw, it's a much more pleasant experience than the usual stamped frame hardware store variety.

Ha!  right. I've used high quality hack saws. No way I would try and use one to cut 2" x 4" aluminum stock or 1/4" thick steel...  ( did plenty of that nasty work when I was 16 and had no choice).
 

Offline blueskull

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Re: Desktop CNC
« Reply #38 on: January 15, 2018, 07:10:49 PM »
So, it has came to an end. Sorry for those who have posted against the Carbide 3D eye candy, but I just pulled the trigger.

From their email, they said the rated accuracy is based on actual measurement of machined parts with only factory calibration, with fine user calibration it can be better.

Their word is "You’ll find that we’re conservative in the extreme when it comes to promising what the machine can do". They also claim that the Z axis id as accurate as X/Y axes.

Also, I asked a YouTube machinist, Winston Moy, and his reply confirms this. Among his 1 year usage, the error is never beyond 0.1mm and his initial unboxing test shows bang on on acrylic and 1mil error on metal.

As for PCB milling, the Carbide 3D guy told me that 10mil/10mil should be a piece of cake as long as I hold my PCB down properly, and use the smallest bit they provide.

From their official forum, there is not a single Nomad 883 Pro version (not KS version) on sale not being bought by someone else in very short amount of time, and I think that means something.

So, the bottom line is I just ordered one, and let's see if it will live up to my expectation.
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Offline rx8pilot

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Re: Desktop CNC
« Reply #39 on: January 15, 2018, 07:17:12 PM »
Good luck, I hope it works out for sure.

Have a look at Harvey Tools. They have some excellent V tools, drills, end mills for this type of work. I have used them for years.



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Offline blueskull

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Re: Desktop CNC
« Reply #40 on: January 15, 2018, 07:19:43 PM »
Have a look at Harvey Tools. They have some excellent V tools, drills, end mills for this type of work. I have used them for years.

I will. The next step is to collect bits, I guess. Expensive hobby, but still way cheaper than collecting multimeters and binning LTZ1000As ;).
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Offline Dubbie

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Re: Desktop CNC
« Reply #41 on: January 15, 2018, 09:26:52 PM »
Also don’t get sucked in with no-name Ali-express tooling. The name brand stuff works a LOT better and when you factor in wasted time and scrapped parts, it can work out cheaper.

When you are cutting aluminium, be aware that you must have some lube on the tool or else the chips will weld to the tool and it will break in a fraction of a second. Recutting chips can also cause this, so you need to clear chips either with vacuum or air or manually with a brush.

Lastly you should seriously look at fusion360. It’s free for you and the CAM is easy to learn and up with the best out there.
 

Offline blueskull

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Re: Desktop CNC
« Reply #42 on: January 15, 2018, 09:46:38 PM »
Also don’t get sucked in with no-name Ali-express tooling. The name brand stuff works a LOT better and when you factor in wasted time and scrapped parts, it can work out cheaper.

I will not. Right now I will first stick with Carbide 3D official tools, then I will start considering rx8pilot's suggestion. I'm not into high volume, low margin manufacturing, so there's no sense for me to save cents on tools and waste time.

When you are cutting aluminium, be aware that you must have some lube on the tool or else the chips will weld to the tool and it will break in a fraction of a second. Recutting chips can also cause this, so you need to clear chips either with vacuum or air or manually with a brush.

According to Carbide 3D, there's no need to use lube, though if I want to do hard metals I will have to.
Regardless, I plan to cut in a pan of lube, just like shown in TSP115. It's worth the trouble even only for noise and dust reduction since I plan to use it as a home lab equipment.

Lastly you should seriously look at fusion360. It’s free for you and the CAM is easy to learn and up with the best out there.

This has came to my mind, but I won't like their subscription model.
I think for now I will stick with their free CAM software which is written by their boss.
If I ever grow out of it, I will consider other options later.
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Offline ovnr

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Re: Desktop CNC
« Reply #43 on: January 15, 2018, 10:22:34 PM »
According to Carbide 3D, there's no need to use lube, though if I want to do hard metals I will have to.
Regardless, I plan to cut in a pan of lube, just like shown in TSP115. It's worth the trouble even only for noise and dust reduction since I plan to use it as a home lab equipment.

Just because the somewhat dubious manufacturer says something doesn't mean it's the best thing to do. Also, while I didn't watch the entire TSP115 video, you do not want to submerge the workpiece in lube if you're doing metals. Chip control and evacuation will be an absolute nightmare. It's fine if you're just engraving a PCB, but for actual milling, it'd be no good.

(Disclaimer: I'm rather unimpressed with the Carbide 3D thing and anyone who touts "Made by Makers!" as a feature lose rather a bit of credibility.)
 
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Offline blueskull

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Re: Desktop CNC
« Reply #44 on: January 15, 2018, 10:47:19 PM »
Just because the somewhat dubious manufacturer says something doesn't mean it's the best thing to do.
Chip control and evacuation will be an absolute nightmare.

Then I think I'm in trouble. The Nomad 883 Pro doesn't came with a chip tray or anything similar, so if I have to add lube without submerging the parts, I will need a way to collect the lube, or just buy a huge bakery tray to house the entire machine.
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Offline ovnr

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Re: Desktop CNC
« Reply #45 on: January 16, 2018, 12:14:20 AM »
Then I think I'm in trouble. The Nomad 883 Pro doesn't came with a chip tray or anything similar, so if I have to add lube without submerging the parts, I will need a way to collect the lube, or just buy a huge bakery tray to house the entire machine.

You don't have to do flood coolant. Just squirt some on while it's working.

If you plan on using a vise, I'd consider adding one of those thick foil aluminium baking/food trays underneath - just cut some holes for whatever fastening method you're using. Add some light waterproofing to avoid leaks. You will want a wet/dry shop vac anyway, so just vacuum up the chips and coolant/lube every so often.

A lot of commercial aluminium machining is done with mist coolant (often ethanol for faster drying), but that's probably not a massively good idea in an enclosed lab. Plus you'd need an air compressor to run it.
 
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Offline rx8pilot

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Re: Desktop CNC
« Reply #46 on: January 16, 2018, 03:23:32 AM »
You can cut steel dry with carbide tools. As stated, aluminum will stick to the gullies of the tool causing them to break milliseconds later. Taking very light cuts rubs the material away, dulling the tool far quicker than going faster and actually cutting the material away.

Lots of non intuitive details in machining. Mist coolant can work well but needs a lot of compressed air. It also throws chips a mist film everywhere - not sure the carbide 3D machine will tolerate much of that.

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Offline rx8pilot

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Re: Desktop CNC
« Reply #47 on: January 16, 2018, 06:43:48 AM »
Look into the concept of 'Chip Load'.

It refers to how much material a cutting tool bites off on each rotation. It is a product of the spindle RPM, the number of cutting flutes and the speed it is being moved through the material.

It is obvious that there is a maximum chip load, but there is also a minimum chip load where the cutter transitions from being a cutter to being a grinder.

Also don’t get sucked in with no-name Ali-express tooling. The name brand stuff works a LOT better and when you factor in wasted time and scrapped parts, it can work out cheaper.

When you are cutting aluminium, be aware that you must have some lube on the tool or else the chips will weld to the tool and it will break in a fraction of a second. Recutting chips can also cause this, so you need to clear chips either with vacuum or air or manually with a brush.

Lastly you should seriously look at fusion360. It’s free for you and the CAM is easy to learn and up with the best out there.

Yes - all of my very high-end carbide tools are lower cost than the various no-name tools I have tried. In some cases, a tool with 10x (or more) the purchase price is still lower cost. Cheap tools slow you down, scrap parts, and have to be replaced all the time. With that in mind, a beginner with a cheap machine tends to break tools more by accident or misuse rather than natural wear. Cheap machines also have big runout numbers on the spindle (regardless of manufacturer claims). Runout kills tools FAST.

F360 is a great option, not sure what the Carbide 3D machine requires. Many of these maker machines have a 'flavor' of G-code or some anomaly that makes it harder to program.


From their email, they said the rated accuracy is based on actual measurement of machined parts with only factory calibration, with fine user calibration it can be better.

I am very skeptical of the claim. It will also change considerably under loads. The system is inherently absent of rigidity and the acme nuts take up backlash with a spring.
Wishing there was one in my area to measure reality. Maybe even borrow a Renishaw ball bar to really paint a picture of its capability.
 
« Last Edit: January 16, 2018, 06:56:25 AM by rx8pilot »
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Offline Koen

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Re: Desktop CNC
« Reply #48 on: January 16, 2018, 07:11:14 AM »
We need a "Renishaw ballbar Without Borders" organization to send free ballbars to manufacturers with outrageous claims.
 
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Offline Koen

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Re: Desktop CNC
« Reply #49 on: January 16, 2018, 07:15:35 AM »
Jokes aside, if you're going to make powder as-in the manufacturer's videos, don't mix lubricant with it. It will only form a thick paste which will clog the tool, heat up everything and break some flutes.

Evacuate the powder, by blowing or vacuuming.
 


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