cirquod - small CNC for home made PCB - Page 1
Forum section: electronics / general

author: eitanma
author_rank: Newbie
timestamp: November 28, 2016, 12:53:11 am
content: Hi.I consider buying a Cirqoid CNC machineI would really like to know how easy is to make a double sided PCB with QFN packages on that machine?I looked all over the web and I couldn't find any relevant videos or examples of that machine at work.My goal is to design a board, solder it and write the code in a very fast cycle,I plan to use the machine just for prototype and order PCB from manufacture after making sure that everything is on place, process that takes 3 weeks.I am willing to pay 3000$ for a good enough tool.Is there any other good alternative? (other then stepcraft)?

author: thm_w
author_rank: Super Contributor
timestamp: November 30, 2016, 11:46:01 pm
content: In the video it looks like they are manually placing the components (although this is from 2013).They don't show a vacuum attachment, although they do sell it on the site. It is absolutely necessary IMO.When you make a double sided PCB, you have to align the two sides well, they show pins in the video. You also need to join the bottom and top layer, this can be done by manually soldering wires or using a machine to "crimp" in the vias. You will need to spend some time in their software to select drill sizes from what you have. Maybe an hour for setup once you have it down?Why does your current PCB process take 3 weeks? You can get 5pc 10x10cm 2 layer PCB in 6 days from PCBway for $65. That means you will be making at least 45 of your own designs (not including consumables like drills and boards), to pay off this machine.

author: janekm
author_rank: Unknown
timestamp: December 01, 2016, 12:51:15 am
content: Quote from: eitanma on November 28, 2016, 12:53:11 amTo mill PCBs at smaller line/space widths you need to either have a really good vacuum table to hold down the PCB tight, a floating toolholder (used on most professional PCB mills like LPKF) or Z-axis mapping.On a small budget I would go with Z-axis mapping, adds a little process time but very practical on a budget.This machine looks pretty expensive for what it is, I bought a CNC mill kit for around $130 that does a really good job at milling PCBs.

author: edavid
author_rank: Super Contributor
timestamp: December 01, 2016, 01:54:50 am
content: Quote from: janekm on December 01, 2016, 12:51:15 amWhich one did you buy?

author: janekm
author_rank: Unknown
timestamp: December 01, 2016, 02:28:29 am
content: I bought this one:https://item.taobao.com/item.htm?id=531855133304&_u=1k1rlm99a40There's quite a few others available with very similar design. It's very sensible, the frame is rigid given the small size, and the controller is using open-source firmware so easy to adapt. I usedhttp://flatcam.orgfor the gerber->g-code conversion, works pretty well. I used the Z-mapping features available in newer versions of the firmware.BTW their video freaked me out a bit by doing PCB milling without proper dust extraction (should be with a real negative pressure enclosure) or flood lubricant, the FR-4 dust is by all accounts not a good thing to breathe in...

author: eitanma
author_rank: Newbie
timestamp: December 01, 2016, 09:31:34 pm
content: thanks for the great answer.I might try one of those myself.in that low price, I prefer to try them before buying something expensive.some other cheap CNC suggestions?

author: tronde
author_rank: Frequent Contributor
timestamp: December 02, 2016, 01:22:56 am
content: Quote from: janekm on December 01, 2016, 02:28:29 amHow did you order from them? I can't manage to get google translate make much sense. How much for shipping to Europe?

author: ralphrmartin
author_rank: Frequent Contributor
timestamp: December 02, 2016, 12:16:37 pm
content: Quote from: janekm on December 01, 2016, 02:28:29 amA few questions:You need an external 24V10A power supply, right?It comes with a GCode interpreter/controller, right?How did you figure out how to put it together? Just watch a video, I guess?How are the items held down on the table? I guess something is fixed to the other side of the board - how does that work?What software comes with it, if any?Any idea of the total weight? (I'm thinking of bringing one back in my luggage).Any other tips, comments that might be useful?Thanks!

author: edavid
author_rank: Super Contributor
timestamp: December 02, 2016, 04:34:54 pm
content: Quote from: tronde on December 02, 2016, 01:22:56 amI think you can find the same one on AliExpress, where the ordering is less challenging.

author: tronde
author_rank: Frequent Contributor
timestamp: December 02, 2016, 05:01:35 pm
content: Quote from: edavid on December 02, 2016, 04:34:54 pmI know. CNC2013 looks similar but more expensive. I would like to know how much for shipping from taobao. Those selling on Aliexpress know how to make a profit from foreignes, and shipping cost can hide a lot of profit.

author: janekm
author_rank: Unknown
timestamp: December 04, 2016, 02:26:31 am
content: Sorry for the late response, I was travelling...Quote from: ralphrmartin on December 02, 2016, 12:16:37 pmIt's included! It's really a crazy cheap package.QuoteYes, comes with an Arduino-derived board with the 3 stepper motor controllers (and some extra I/O for optional spindle motor control / Z-mapping though you have to figure that out yourself).QuoteYes, the seller has put together a pretty decent video (on a Chinese video sharing site, so will be slow outside China) and they even sent me an English version of the assembly manual. Assembly wasn't too tricky but takes pretty much a whole day.QuoteThe table is made from "T-Slot" aluminium extrusion and you can use special screws to hold things down. There's many options, you can just hold things down at the edges with screws and washers. For PCBs, using double-sided sticky tape works well though it's a bit messy to clean up.QuoteThe seller supplied a dubious copy of Artcam, which is a specialised software for generating G-code from 2D height map files. Fun to play with, you can make surprisingly pretty engravings in wood. Some other stuff too. I had to ask them for the link on the taobao chat. They also included some common open-source software for sending G-code etc.QuoteIt was pretty heavy, I would guess close to 10kg. I don't have a suitable scale to hand unfortunately.QuoteThe firmware used on the driver board is GRBL. The seller installed an older version but upgrading to the newest stable release worked no problem.I've attached the assembly manual (with reduced image quality), I think that gives a good idea of what's involved in putting it together etc.It is a cheap kit, and some of the component parts are of cheap quality (like the linear bearings), so I wouldn't expect it to last for years of heavy use. But it's a great start to experiment with CNC tools, and certainly "punches above its weight". I'm planning to modify mine to a glue dispensing robot as I have access to a larger CNC engraver now.I used bCNC (https://github.com/vlachoudis/bCNC) for sending g-code for PCB milling, which supports auto-levelling / z-mapping. You'll have to attach some wires with alligator clips to the controller PCB for this, one end attaches to the PCB and the other to the cutting tool so GRBL can sense when the tool touches the PCB. Flatcam for generating the g-code from gerbers. I covered the PCB in WD-40 to lubricate the cutting tool and cut down on dust. I used a nail-polishing pad to remove the burrs after milling.Quote

author: janekm
author_rank: Unknown
timestamp: December 04, 2016, 02:39:51 am
content: Quote from: tronde on December 02, 2016, 05:01:35 pmYes, I think this one:https://www.aliexpress.com/item/Diy-CNC-engraving-machine-working-area-180-140-35cm-PCB-Milling-Machine-CNC-Wood-Carving-Mini/32619426954.html?ws_ab_test=searchweb0_0,searchweb201602_3_10065_10068_10084_10083_10080_10082_10081_10060_10061_10062_10056_10055_10054_10059_10099_10078_10079_426_10073_10102_10096_10052_10050_425_10051,searchweb201603_6&btsid=b7f60894-fffd-402b-bd16-3ca38514dce4is the same kit as the one I bought.It's not always possible to order from taobao directly to international addresses (though to some countries taobao now offers a re-mailing service themselves). Usually you would use a "taobao agent" who will order the item for you from Taobao and then ship it to you (the typical charge is 10% of the item price, so that would be a bit less than what the Aliexpress sellers quote, I think). It's a heavy kit, so I think the shipping costs listed on the Aliexpress listings may be realistic.It's worth having a look at "CNC3020" type CNC engravers too (many different models from different factories), those are a big step up in quality typically though a fair bit more expensive. They are not necessarily more capable for PCB engraving though, as a smaller frame makes it easier to reach the necessary accuracy. But worth looking into for anyone interested in a more wider range of basic CNC milling.

author: tronde
author_rank: Frequent Contributor
timestamp: December 04, 2016, 03:55:39 am
content: Quote from: janekm on December 04, 2016, 02:26:31 amYou just dump the code from the PC into the controller so you stay clear of communication problems on the USB bus?

author: janekm
author_rank: Unknown
timestamp: December 04, 2016, 08:00:10 am
content: Quote from: tronde on December 04, 2016, 03:55:39 amYou use a piece of code on the PC called a "G-Code sender" (like bCNC or chilipeppr or a few others) which sends the G-code to the firmware on the controller board. It uses a serial over USB protocol. The grbl firmware on the controller board has a small buffer (planner buffer) of g-code commands that it maintains so it can cope with a certain degree of USB latency, yes. The grbl firmware interprets the g-code and sends steps to the stepper motor controllers.

author: ralphrmartin
author_rank: Frequent Contributor
timestamp: December 09, 2016, 01:28:38 pm
content: Thanks for your very detailed reply, and the instructions!