My Cheapo Chineese 3020t mini CNC Build (more like improvements) leanring all the way

Hello everyone, I thought I would do a bit of a build thread showing my experiences with my new cnc adventure. From looking at other threads on here 90% of everyone seems to be pretty competent, so for the remaining 10% who may be afraid to ask daft questions my build thread may be more applicable to you as I know absolutely nothing, so im learning each day.

I have chosen to buy a mini CNC machine which is 4 Axis and has a bed size of 240 x 340 with a working area of 200 x 400. I paid £420 for this Chinese machine which was actually stored in a warehouse in Germany. The benifit of this was that it arrived in 3 days and zero duty, clever thinking by the seller.

Here is the machine
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I had to assemble it slightly in the sense of attaching the motors and plugging them in, simply really.
My mate took the machine to his to see if he could start setting the new pc (purpose bought for this machine) to communicate with the machine, we are using a usb connection and I have purchased Planet CNC software which can be obtained from here:
https://planet-cnc.com/software/
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Whilst my mate was working on the machine it gave me chance to try and make some space at my workshop (which is very small) for the pc and machine. Decided to put it next to my booth
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I purchased a cheap workbench from the bay which suits the machine nicely, slowly getting there, will be a nice little workstation once finished

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Hi Ravi and welcome to the forum,

Thanks for the share, will keep an eye out for what you get upto :thumsup:

Cheers Lee mate.

Well a bit of a small but positive update, managed to sort the work area out for the cnc machine and the control pc, included a few essential tools and measuring equipment. Extraction system next.
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As this machine doesnt come with any limit switches as standard I have purchased some very small and discrete switches, I have also sourced some nice and small 2 pin connectors so they can be unplugged at any time with ease.
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As the control box which came with the machine had a faulty x axis driver I didn't want to exchange it for another cheap one, so I asked a few question on here and got some very good responses, all of which were pretty much above my head. As I have already purchased the Planet CNC software I thought it would make sense to purchase their own control box as I think the support they can provide would be very beneficial to myself being a complete novice. The box arrived on Monday, only ordered it on the Friday so I was very impressed with the delivery time. Once arrived I unpacked it, looked at it a bit confused then managed to find a spare half hour to start assembling it. Work was halted though when I realised my soldering iron was at home.
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Well I managed to have a good session on the control box tonight and my first ever stab at soldering, its a lot harder than it looks.
First job was to solder the pins to the board for the motor connections and other plugs which in not sure of lol
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Then it was to solder the small on off switch and power from the mains plug
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Here is a pic of the old driver board v the new Planet driver board, you can see the quality difference straight away (I just hope this one works)
old
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New
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Now I had to wire in the cables for the limit switches, this was a little bit fiddly, I used a few small pieces of heat shrink to help keep the cables together.
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Now to attached the ribbons for each axis.
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Thats all I managed last night, all that needs doing now is wiring the octocoupler in (which I have no idea what that is)

Really happy with it so far, hopefully have it fired up in the next few days fingers crossed

Its hard to see and I am not picking holes but the soldering on the board does not look good. Its looks like it is balled up that is an indication of a newbie not leaving the iron on long enough for the sold to flow (common mistake) I would re flow some of the joints.

pick away clive mate
this is what I need so I welcome any advice mate. Before I made that sort of ball on the top I filled the hole underneath with solder, then tried to get that dome shape just for neatness, but I did fill the prong on the switch. Not to sure if I soften the solder I can do much else

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Originally Posted by ravihotwok

pick away clive mate
this is what I need so I welcome any advice mate. Before I made that sort of ball on the top I filled the hole underneath with solder, then tried to get that dome shape just for neatness, but I did fill the prong on the switch. Not to sure if I soften the solder I can do much else

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Are you applying the solder to the iron and then putting it on the part if so that is wrong. You need to put the iron on the part and then apply the solder to the part and you should see it flow. Some people when learning just dab the iron but the part needs about 1-2 secs of heat depending how big the iron is.

No mate, I watched a few tutorials on youtube, I held the tip of the iron against the prong on the switch for a short while then placed the wire against the prong, as soon as it melted I let it fill the hole till about 3mm, then I removed the wire and slowly lifted the iron away to leave that dome shape. I was also careful to keep the end of the iron clean with a special sponge I bought from maplin. I never realised just how fiddly soldering is! and time consuming,

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Originally Posted by ravihotwok

No mate, I watched a few tutorials on youtube, I held the tip of the iron against the prong on the switch for a short while then placed the wire against the prong, as soon as it melted I let it fill the hole till about 3mm, then I removed the wire and slowly lifted the iron away to leave that dome shape. I was also careful to keep the end of the iron clean with a special sponge I bought from maplin. I never realised just how fiddly soldering is! and time consuming,

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But when did you apply the solder?

time wise? think it was about5 - 8 sec? not too sure if im honest clive mate, but when it was melting plenty seeped in

Are you using lead free solder?

No think its 60/40 lead but would have to confirm

yep its 60% lead

The reason I asked, is lead free is a bit harder to work with, and easily results in joins like your photos.

Ideally you should be aiming for having the soldering iron in contact for less than 10 seconds. For heat sensitive components, even shorter than that.
Process should be - clean tip to remove old solder(that's what the wet sponge is for - the flux burns of, so you want any remnants of solder wiped off), apply blob of fresh solder on the tip, hold tip against what you're soldering, as soon as the solder starts to flow onto the leg/PCB, feed in enough to get a good join aiming for the contact point between tip and component, pull solder pulled away, pull soldering iron away.

Having a decent sized soldering helps. Too small and you have to hold it on for too long to get solder to flow, too big and you risk overheating things if you hold it on too long.

thats very helpful and exactly what I was aiming for as you have echoed what I watched in a tutorial, but remember this is my first time so even though the theory is there putting it into practice is another matter lol. Hopefully ive not cooked anything, just waiting on further instructions on the advanced addons for this box from planet then I should be able to fire the thing up.

Managed to get a bit more done tonight. I have decided to install limit switches to help prevent damage and to aid homing. I have decided to put 2 each of the x and y axis and one on the z axis. I have soldered 2 small tails to the switches in NC configuration and crimped a small 2 pin plug for future maintenance/removal
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Enjoying your thread Ravi, thanks.

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Originally Posted by ravihotwok

thats very helpful and exactly what I was aiming for as you have echoed what I watched in a tutorial, but remember this is my first time so even though the theory is there putting it into practice is another matter lol. Hopefully ive not cooked anything,

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First job was to solder the pins to the board for the motor connections and other plugs which in not sure of lol

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Ravi I would re solder (re flow all the motor connections that look and are bad on that board) as they will give you trouble and it si possible that could blow the drives if there is a dry joint. The resistors look a lot better.

All you need to do is put the iron back on them and when the solder starts to flow with the iron still on apply a bit more solder and the flux will do the rest. I know this may be controversial but full lead solder is a lot easier to use.

ffs!

No problem clive, will take that board out tonight and do as you say to make sure as the last thing I want is parts burning out, will be doing it around 7pm tonight so will do one re solder and post a pic up to see if its satisfactory before I crack on with the rest mate, be handy if you can keep an eye out pal.
I appreciate everyone's input :-)

Cheers Andy mate

right im at work doing a bit of skiving watching homeland and messing with this control box, I have re soldered the plug connections as advised, pelase have a look and give me your thoughts, don't think I can do much better if I'm honest
before
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And now after re soldering
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Ravi They are better but some are not good. It does take practise I think you said you have leaded solder.

You will have to power it up and see. Remember always apply the solder to the joint (its ok to wet the iron first with solder) It should run and not ball up. What is the wattage of your iron?

i have balled it up deliberately, once I had allowed plenty to go into the terminal i then gently moved the iron in a circular motion to ensure the solder didnt interfere with the next one. Iron is 30watt matey

Too much solder, you should be able to see the shape of the parts after they are soldered.

Did a bit more on the machine this weekend, my new 600w spindle and pwr supply arrived as well
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I have allso installed the limit switches, 2 on each x and y axis and one on the z axis
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A common problem with this model of cnc machine is excess play on the z axis, this is caused by a small gap from the top of the screw and the bearing just where it meets the motor. It is only about 1.5mm but is enough to worry you. Using a 3d printed washer I have solved this problem and now there is zero play in the z axis, got the idea from a funny chap off youtube.

Here is the excess play before
https://www.youtube.com/watch?v=r9aK...ature=youtu.be

Here is how I solved it:
I started with printing some washers
8mm id 11mm od 2mm thickness
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Now to remove the motor, and then the 2 retaining screws on top of the bearing
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Now slide the printed washer onto the screw
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Now install the bearing again, you must make sure that the bearing is flush with the top of the housing it is seated in, I had to sand about half a mm off to achieve this, once happy tighten the 2 retaining screws and then install the motor.

Here is the result
https://www.youtube.com/watch?v=YBEN...ature=youtu.be

No play at all and the axis still moves nice and freely. An easy fix to what really should of been sorted at factory.

Hope this helps someone in the future :-)

Been very busy with work so been restricted when I can play with the machine, I have been plodding along in the back ground though. I have no fully re wired the stepper motors to the controller, I have binned the cheap 5 core unscreened power cables for a thicker screened 5 core cable and freshly soldered them to the plugs. These were a complete nightmare to try and fish through the cable track but I got there in the end. Once wired up the motors were making a high pitch noise, also when trying to jog any of the axis they just seemed to move back and fourth which is a tell tale sign of the wrong core pairs being wired up. For anyone interested, my motors are 4 cable motors, which means it has 2 coils with 1 pair of cables per coil. I used the multimetre to find when 2 of the cables were connected a circuit was made, that way I could establish which cables were paired together. The I wired one pair to pins 1 and 2, and the other to 4 and 5 of the 5 pin plug and hey presto it worked well. I have made the length of the cables just shy of 3m for now as im making a full enclosure so thought it is much easier to cut the cables back than to add in AND RE-FISH THROUGH THE CABLE TRACK LOL

Anyway here is a few pics, limit switches are to be done tonight then I can start setting the controller up through the software which I really have no idea how to do but got plenty of literature from Planet CNC to guide me, would like to mention they have been very supportive throughout this build even though I have been bombarding them with daft question constantly.
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I have no fully re wired the stepper motors to the controller, I have binned the cheap 5 core unscreened power cables for a thicker screened 5 core cable and freshly soldered them to the plugs.

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Did you ground the screens at one end?

Nope, Planet said there was no need to?

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Originally Posted by ravihotwok

Nope, Planet said there was no need to?

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That must be ok then:concern: The vast majority on here would disagree I think.

Screened cable without the screen being grounded is acting like un screened cable. so ground the screen at one end. It may not make a differnce, but if you have screened cable, it makes sence to use it how it is intended to be used.

Thanks Gary, can you advise on how the best way to earth it please? can I earth it to the machine? or to the control box? Any examples?

Cheers

Thanks Gary, can you advise on how the best way to earth it please? can I earth it to the machine? or to the control box? Any examples?

Cheers

in the control cabinet and to a star point.

and make sure the cabinet is also grounded.