My new 6040 improvement plan.

**PaisleyPCdoctor** · 06-12-2017

Second (and probably the biggest of the lot)- SHIELDING- or lack of it!

Absolutely nothing is shielded not even the VFD cable!

I started with external cables to Spindle and Stepper motors.

Supplied VFD cable looks nice flexible rubber 'pond flex' cable. It's plain unshielded 0.75mm2 3 core and earth. The earth wire IS connected to spindle (thank god), but no shielding.

I replaced the entire cable with shielded 1.5mm2 CY control cable. To be extra careful, I also added external copper braid shield. It's now double screened.

I didnt replace the stepper cable, I suply added a copper braid sleeving to the entire length. Obviously, the sleeve is connected to earth....

Actually, no. The aviation connector barrel on the chassis is making contact with paint, not metal. NO EARTH CONNECTION! I had to scrape off paint inside the case to sort that.

Next job is shielding the cables inside the control box, then probably moving VFD to its own enclosure.

Click image for larger version.

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**magicniner** · 07-12-2017

(X) Location, (Y) Location, (Z) Location!
The rest is just window dressing if the first 3 are not worth the cardboard it was shipped in :D

**PaisleyPCdoctor** · 07-12-2017

Originally Posted by magicniner

(X) Location, (Y) Location, (Z) Location!
The rest is just window dressing if the first 3 are not worth the cardboard it was shipped in :D

Eh?

**pd110961** · 07-12-2017

Hi Paisley.. where are you in the country mate?

**PaisleyPCdoctor** · 07-12-2017

Originally Posted by pd110961

Hi Paisley.. where are you in the country mate?

I'm in Paisley. Scotland.

**m_c** · 07-12-2017

I suspect Nick was on the sauce last night ;-)

But his point was if the basic machine can't hold tight tolerances, then everything is else is superficial.

Shielding is not as big a problem as people often think it is. None of my Denford machines came with anything shielded other than two sensors on the Triac mill. Everything else, including the spindles (VFD on the Cyclone lathe, and DC spindle on the Triac) used unshielded wiring, but then they're not using TTL level logic for inputs.

**PaisleyPCdoctor** · 07-12-2017

I get that, however, as it's often repeated on this forum- not all China cnc are the same. Much of the reputation was for poor electronics was from early controller boards and VFD etc. I was very careful to get one with a newer controller (HC4-IV), decent steppers and a good spindle. There's nothing inherently wrong with the table and gantry design.

I know my way around electronics, so I wasn't bothered about doing some extra work to improve it. Even without the improvements, it hasn't glitches on me yet. It's done everything I've asked of it perfectly well.

At £1800 it's not the cheapest out there- I certainly wasn't going to spend £10k+

Plenty of people making really cool stuff with 6040's.

**m_c** · 08-12-2017

There is plenty wrong with the basic machine design.
If you're only doing softer materials with light cuts, it's not a problem, but if you try pushing the spindle, you'll get resonance/poor cuts.

If you have a DTI, try setting it up against the spindle noseat a typical cutting height, then apply some pressure against the spindle and see how much deflection you get. Having three sets of unsupported rails between the bed and the spindle does not produce good rigidity.
Then try testing for backlash. The setup used for the ballscrew endfloat is a couple single row ball bearings (which are usually cheap rubbish), with preload controlled via a single nyloc nut. Then the stepper motor couplers will most likely be cheap aluminium bellow type, which will crack if driven hard.

Plus the general tolerances will be questionable.

And in case you're wondering why I know all this, is I bought a 3040z as the base for a digitizing machine, knowing full well it's shortcomings. It does it's job as digitiser, but I certainly wouldn't want to use it as a router and expect it to produce good quality cuts and not need continual fettling.

**PaisleyPCdoctor** · 08-12-2017

I understand what you're saying and I agree to a point. Of course it's not going to be as good as a £10k+ machine, but I don't think it's as bad as you say. The newer models are build far better than the older (coupla years only) models. Either way, my only option is to try to improve in its weaknesses as much as I can and learn whilst doing it. It's fun anyway.

Take a look at this video (especially around 8minutes in). He's on my school of thought that the wiring is the main problem now, not the mechanics.

https://youtu.be/fdfJ_WZTxJY

**Doddy** · 15-12-2017

Originally Posted by PaisleyPCdoctor

Actually, no. The aviation connector barrel

I've heard these referred to as aviation connectors before now - as I understand it they are used for the headphones on radios. So, yes, they fly, but let's not oversell them. My main concern with them is these (and they are in common use for these machines) is that they aren't really rated for the currents that you might expect. For example

http://www.cliffuk.co.uk/products/cliffcon/zc.htm

You can see these are rated unto 1A. Probably not much of an issue for a small machine - your switching currents are going to be around 1.5-3A, but clearly out of spec for the connectors. My last iteration of <strike>upgrading</strike> updating my controller I replaced all with XLRs.