Structure to my own CNC - Page 1
Forum section: electronics / projects

author: Jasonbit
author_rank: Regular Contributor
timestamp: August 06, 2018, 11:56:03 pm
content: Hello folks,Maybe I am on wrong place (sorrry) but I think this place it is the best site to put my question. I have this stuff:1-Motor Drive Shield Expansion Board L293D For Arduino Duemilanove Mega2560 UNO - (https://www.ebay.com/itm/Motor-Drive-Shield-Expansion-Board-L293D-For-Arduino-Duemilanove-Mega2560-UNO-/170910733083)2-CNC Shield V3 3D Printer+4xA4988 Driver +UNO R3 For Arduino w/USB Cable Hot - (https://www.ebay.co.uk/itm/CNC-Shield-V3-3D-Printer-4xA4988-Driver-UNO-R3-Arduino-w-USB-Cable-Hot-/142344959395?hash=item21246bb5a3)3-A3967 EasyDriver Shield Stepper Motor Driver Module V44 For Arduino 3D Printer - (https://www.ebay.com/itm/A3967-EasyDriver-Shield-Stepper-Motor-Driver-Module-V44-For-Arduino-3D-Printer-/400522271040)I really think if the best option to my DIY it is buy prototype pcb on service online, like ashttps://jlcpcb.com/, or try built my owner cnc at home and make my owner prototype pcb. I like this video:I'd rather build my own CNC. But to I do this I need find a cheap sctruture (Kit) cnc. Where (ebay, banggood, aliexpress, etc) do you suggest search for, and what's key words I should use on my search?Thanks

author: james_s
author_rank: Super Contributor
timestamp: August 07, 2018, 03:27:22 am
content: The easiest by far is to order PCBs online, although that does require waiting. If you want to build your own CNC plotter that's a deceptively large project, but old inkjet printers and flatbed scanners are probably a good source of suitable mechanical parts.

author: cncjerry
author_rank: Unknown
timestamp: August 07, 2018, 05:03:45 am
content: Look at my userid, CNCJerry. I've been working with CNC and 3D design since the early 80's and tried everything you can think of to mill PCBs and never found anything reliable. There are people that can show you one or two boards, maybe more, but there are always problems. The swarf that builds up while milling is hard to clean, for instance. It is also hard to hold the boards flat and i've tried everything including a vacuum table.You are on the right track with plotting direct to the board. It would be better though, if you spun the pen. Bu the issue with this method is that you will get sections from over-drawing that will cause a gap. Try just drawing a few lines on a bare board both directions and you will see that once the ink dries and you then cross it, you sort of scrape off the prior line a little. So it is hard to get a consistent mask.I have 10's of thousands in milling machines and I do on occasion iso-mill a board, but it is faster to just order from one of the many suppliers and just hang the project up for a few days.The new printers that use the silver ink are pretty cool but very limited and I'll bet soldering is tough.I would hang it up before you spend a lot of money on poor results.Jerry

author: Jasonbit
author_rank: Regular Contributor
timestamp: August 07, 2018, 08:44:15 am
content: Thanks to yours reply and testimonials. I have read a lot about CNC homemade and I know it's a complex project. But, since I already have the material, I intend invest on a cheap structure CNC. At least for see the motors to rotateRegarding printer schematic directly on board, I need really a process cheap and easy to test my prototype boards before sending to production. As I said, I use JLCPCB service online to make my PCB. The pcb, normally, are cheap, but the sending represent more 80% of the cost. For example, right now I have a board prototype to make and the cost are $ 30. The pcb costs only $ 2!Do you suggest any service online where I can make my prototype pcb, I don't care if the board has a less professional aspect, but at least the cost is more cheap!ThanksCNCJerry,On this video the scott talk about some problem which you said:

author: james_s
author_rank: Super Contributor
timestamp: August 07, 2018, 03:39:21 pm
content: There are loads of online suppliers of nice high quality boards for very low cost. I often use smart-prototyping.com but there are others. For small boards it was around $10 for 10 boards, so $1 each. Double sided, solder mask and silkscreen on both sides, quite nice.For me the holy grail in home PCB production would be a laser or inkjet printer that can print a quality etch resist directly on bare copper without a lot of screwing around.

author: Jasonbit
author_rank: Regular Contributor
timestamp: August 07, 2018, 03:51:40 pm
content: Quote from: james_s on August 07, 2018, 03:39:21 pmThis is would be awesome!Something like this:

author: Mechatrommer
author_rank: Super Contributor
timestamp: August 09, 2018, 04:18:03 pm
content: have you seen this?

author: Jasonbit
author_rank: Regular Contributor
timestamp: August 09, 2018, 05:14:31 pm
content: Quote from: Mechatrommer on August 09, 2018, 04:18:03 pmThis is yours video? I see many video and project around web about CNC homemade but I have some doubts about reliability this project. The precision, along various passages is guaranteed? The structure guaranteed precision?Note: I know which in this environment the best way isn't to complicate. PCB with tiny path wouldn't be a good option in this type machine.

author: Mechatrommer
author_rank: Super Contributor
timestamp: August 09, 2018, 05:34:31 pm
content: Quote from: Jasonbit on August 09, 2018, 05:14:31 pmnot that important...Quote from: Jasonbit on August 09, 2018, 05:14:31 pmwhat do you expect?(esp if it comes from me?)

author: Jasonbit
author_rank: Regular Contributor
timestamp: August 09, 2018, 05:53:09 pm
content: Quote from: Mechatrommer on August 09, 2018, 05:34:31 pmI expect, at least that, which I can draw a tiny path pcb (more a less 2mm), away from each other, 2 mm. To reduce error and complexity the structure and system I am available use only pcb one side.

author: bob225
author_rank: Frequent Contributor
timestamp: August 09, 2018, 06:00:12 pm
content: I have built a few cnc machines over the years, the repeatability of a cut is the hardest thing to obtain, 1mm out on the on the x/y/z is the difference between cutting the board or running the bit into the waste board and snapping a mill bit what can get expensive quicklyThe simplest way for one off boards is press and peel, and etch the board with Di-Sodium Peroxodisulphate Hexahydrate what's miles easier to clean up the ferric chloride and doesn't stain everything it touchesIf your really interested in cnc have a look at the openbuilds forums and the 100's of projects in the gallery

author: Jasonbit
author_rank: Regular Contributor
timestamp: August 09, 2018, 06:05:23 pm
content: I am thinking build a CNC to draw schematic with permanent ink pen (https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwjykICfx-DcAhXyzIUKHV4OB4cQjRx6BAgBEAU&url=http%3A%2F%2Fzmarket.bg%2Fpisane%2Ftankopisec-faber-castell-ohp-f-green.html&psig=AOvVaw1ubgohLnKXbqsO8B7ozmdu&ust=1533924238286715) and remove copper with ferric chloride. What do you think about this idea?

author: Mechatrommer
author_rank: Super Contributor
timestamp: August 09, 2018, 06:19:06 pm
content: Quote from: Jasonbit on August 09, 2018, 05:53:09 pmi use 0.25 - 0.3mm traces clearance. clearance is not the problem, the problem is when i tried to use smaller than or equal to 0.3mm trace width, then i'll have occasional or minor correction by hand (pen) drawing later due to over "etched" by the plotter, so i prefer to stick to 0.5mm and greater trace width. shorted traces or to ground pour due to under etched is also possible, correction correction correction at post processing, but nothing that serious to make me banging my head on the wall, maybe minor 1 or 2 correction, or 10 the most. if you can spot in the attached picture there is soic package, thats 1mm pin apart, it still can reproduce pour in between, so no problem there. btw i'm not a fan of "pourless pcb" like most youtubers did, if i have a machine like in the OP, the pen will not be able to catch up, or i have to replace it in every 1 or 2 board production, to my suspicion. anyway i call the machine prototype 'Bethan" (Better Than Hand), fwiw...Quote from: Jasonbit on August 09, 2018, 06:05:23 pmremove copper with ferric chloride is exactly what i did after the "machining" process.

author: JS
author_rank: Frequent Contributor
timestamp: August 09, 2018, 11:24:55 pm
content: I use toner transfer and a laminator instead of an iron. I tweaked the temp and pressure a bit up and I get very reliable results, with traces much smaller than what you are talking here, my first 0.5mm pitch went fine in the first attempt. The celan up of the paper is the harder part, the better the paper the easier it gets.Sometimes you need the boards right now, and waiting a month like it would be here is way too much. Even local (and expensive) pcb makers take a looong time last time I asked, a prototype run in over a month is nuts! And I got the laminator for what five 100x150mm PCB prototypes would cost.For me is more of a trouble making cases than PCBs so I'd like to have a CNC to do some metal working or at least a 3D printer but plastik kind of sucks when noise is a thing...JS

author: Mechatrommer
author_rank: Super Contributor
timestamp: August 09, 2018, 11:51:50 pm
content: yes toner transfer should be the next evolution, but until the printing drum is fungus resistance esp in my climate and can print black enough (more than your black). my lazer printer grew spider like shapes when printing every time just few weeks after purchase, dougghh! i know it can be cleaned which i did, its still there and its funny when a printer that needs major servicing just few weeks after purchase. any further improvement using fancy papers is pointless imothis is my 2nd laser printer after the 1st one decommisioned for the same reason, and when i buy lazer printer, it has no other usefull purpose other than printing toner transfer pcb, which is done not frequently, what a waste.

author: james_s
author_rank: Super Contributor
timestamp: August 10, 2018, 01:06:52 am
content: I've been using toner transfer for years and it works quite well once you get the process dialed in. Still, being able to print resist directly onto bare copper would be amazing. A digital photo-plotter or a projector on a stand like a photographic enlarger might work very well for photo-resist but the pre-coated boards are expensive and my friend used to coat blanks himself and getting an even coat was always a challenge.

author: JS
author_rank: Frequent Contributor
timestamp: August 10, 2018, 01:18:11 am
content: The part I don't find appealing of the photo sensitive etch resistant approach is the ammounts of steps in the process, first you need to print then to apply the photo resist (using the photo resist sheet instead of the ink seems a reasonable approach, a friend uses than and has no trouble) then reveal, clean the PCB and only then go to the etching. With toner transfer you save a few steps, no exposing or revealing but you still need to clean the board but with water, so much less messy. Over all it's cheaper and faster and I'm pretty happy with what I get from there.The only reason for me to get the insolator would be if going for solder mask application, which would be nice but I don't think I'm doing that any time soon, looks like too much for the self etched PCBs, if I had a way to make nice vias and align really nice the two sides I might then consider the solder mask...JS

author: Jasonbit
author_rank: Regular Contributor
timestamp: August 15, 2018, 01:52:21 pm
content: I am thinking choose the method Toner Transfer (Laser Print). I watched this video:and I was fascinated by the simplicity of the process. What do you think about this? When you talk about your experience do you do talk like this process on video?Which paper type do you suggest I use to print circuit? Paper Glossy, for example?ThanksNote:Ok, this process don't require a structure CNC, but for now I really need choose a method cheap, faster and easier to make my prototype pcb.

author: Jasonbit
author_rank: Regular Contributor
timestamp: August 21, 2018, 11:47:33 am
content: What do you think about this article?https://www.instructables.com/id/PCB-Laminator-on-the-Cheap/

author: In Vacuo Veritas
author_rank: Frequent Contributor
timestamp: August 21, 2018, 01:19:52 pm
content: Wow. You're going to spend hundreds of hours and dollars so you can make low density 1970s through hole boards? Yeah, that's a big help in 2018.

author: ebclr
author_rank: Super Contributor
timestamp: August 22, 2018, 12:40:55 pm
content: Why this sarcasm, Let them do whatever they want it's a learning process, A comment like yours does not add nothing

author: Mechatrommer
author_rank: Super Contributor
timestamp: August 22, 2018, 01:25:56 pm
content: Quote from: ebclr on August 22, 2018, 12:40:55 pmwhat to add if its nothing? imho its actually a "constructive" comment in different way. when you start with thinking of building your own CNC and people have spent their time giving advice on CNC and then later asking about the normal way of pcb making with toner transfer, then you must have something wrong in the mind, a negative feedback should get you back on track. thats how it suppose to be, but sometime the not supose to be happened.

author: In Vacuo Veritas
author_rank: Frequent Contributor
timestamp: August 22, 2018, 02:49:57 pm
content: Quote from: ebclr on August 22, 2018, 12:40:55 pmIf I want bacon I could raise a pig, or just go to the store. Do you want bacon or do you want drama?PS: A double negative is like passing a signal through two inverters