NEW MOSHI LASER DSP UPGRADE

[crozza]

I have replaced the X motor with a Nema 17 and the heat issue is gone, so it must off been a bad motor. the nema 17s are a lot bigger in size to but fit perfectly.
Ian

[wctx1977]

I have replaced the X motor with a Nema 17 and the heat issue is gone, so it must off been a bad motor. the nema 17s are a lot bigger in size to but fit perfectly.
Ian

Hi crozza,
How does the new nema perform compared to the ones you just removed from your table? are they smoother? I might do the same since one of my motors (x) gets hot also

[Tech_Marco]

For the K40, the X-axis motor will get very hot when the machine in idle. You need to limit the current to 0.6A on the stepping driver. Personally speaking, I don't think that you should swap the motor if it still works. May be spend the money to the air-assist laser head or swap the focus lens will get more benifit.

From my test, K40 can reach 300~350mm/s. Sometimes it may reach 400mm/s but missing step or lock-up could happen . So, try not to drive it over 300mm/s. In addition, you may want to put some bearing oil on the two axis.


Marco

[wctx1977]

For the K40, the X-axis motor will get very hot when the machine in idle. You need to limit the current to 0.6A on the stepping driver. Personally speaking, I don't think that you should swap the motor if it still works. May be spend the money to the air-assist laser head or swap the focus lens will get more benifit.

From my test, K40 can reach 300~350mm/s. Sometimes it may reach 400mm/s but missing step or lock-up could happen . So, try not to drive it over 300mm/s. In addition, you may want to put some bearing oil on the two axis.


Marco

Thanks marco, I'll give it a try. By the way, how do I know what size or type of lens does my machine came with ? I'm considering on getting one soon.

[crozza]

I found that the Nema motor does run a lot better and smoother.
I do mostly engraving than cutting.
I gave it a good run and it didnt even get warm.
It also runs a lot quicker without missing a beat.
Definately worth the change.
I havent changed the Y axis one yet as its running really well and not giving me any trouble, nor does it get hot.
If you change the Y axis motor dont forget to order the dual shaft version unlike the X axis one that is single.
I will fit mine to my bigger x/y chassis when I get round to making it.

Ian

[Tech_Marco]

Hello Ian:

If it works out better, please share your NEMA model info and the pulse setting on the DSP card. It may help other folks for setting up the controller.

I'm still using the original motors for my test and I found that the art work came out was pretty good. But I haven't had a chance to swap it to NEMA, so I really don't know the difference . I was thinking that certain area of K40 were lacking and performance was limited, especailly for the sliding guide and the roller. If it gave a boost on performance and cost is affordable, then I have to say "why not"

But I admitted that with hands on doing an upgrade on K40 is full of fun, plus a little frustration of course. I remembered that when I were doing upgrade for the K40 by giving it a new controller TB650, the original K40 then could handle jobs that was impossible before the upgrade. It could do vector cutting and laser head could turn 360' degree so smoth. The feeling was so good! The original K40 can't handle vector cutting but raster engraving only. Plus, it's so slow and the Moshi was terrible (what a junk actually). But after the upgrade even the manufacturer were stunned with performance and asked me 'how to', ha..ha...

Great job!

Marco

[Tech_Marco]

See the air-assisted I just posted:
http://www.lightobject.com/Product3.asp ... egoryId=17

[Tech_Marco]

See the air-assisted laser head I just received.
http://www.lightobject.com/Product3.asp ... egoryId=17

Only 30x available at this time. With help from this module, the power can be boosted by 20%. I could cut 3mm expozy glass with the new laser head or 2.5mm without


Marco

[Tech_Marco]

For the K40, the X-axis motor will get very hot when the machine in idle. You need to limit the current to 0.6A on the stepping driver. Personally speaking, I don't think that you should swap the motor if it still works. May be spend the money to the air-assist laser head or swap the focus lens will get more benifit.

From my test, K40 can reach 300~350mm/s. Sometimes it may reach 400mm/s but missing step or lock-up could happen . So, try not to drive it over 300mm/s. In addition, you may want to put some bearing oil on the two axis.


Marco

Thanks marco, I'll give it a try. By the way, how do I know what size or type of lens does my machine came with ? I'm considering on getting one soon.

K40 must use 18mm or smaller and the focus point is 50.8mm by default. Swapping with a better ZnSe focus lens with an air-assisted laser head can boost the power by as much as 30%. If pure oxygen used, it can boost at least 50% more power but must be handled with care!

[waltfl]

Hi
I have replaced the Y motor with a nema KL17H247-168-4B from keling it worked super but you have to change the hole in the pulley if you have the version with 5mm axel also the couppler on one site ( half) for the pulley take a 1/4 inch drill bit measure the diameter they are differ about 1/132 and you need the smalest one or better teke a reamer then you have to press sit the pulley. take the short end for this. to press sit take the motor set it on the long end of the axel and put the pulley on the short end then take something like a piece of brass and carefully give it a light blow with a . the probleme is that the most pulleys in the K40 are only 18 teeth and I could not find one anywhere MXL 18 teeth with a 6mm bore only 20 teeth but then I needed to change both sites and the extension axel too.
here are the settings I did not replace the X axis motor jet it gets hot but it still works fine set on 1.0A 1600 steps.
download/file.php?id=690&mode=view.
greetings
walt

I found that the Nema motor does run a lot better and smoother.
I do mostly engraving than cutting.
I gave it a good run and it didnt even get warm.
It also runs a lot quicker without missing a beat.
Definately worth the change.
I havent changed the Y axis one yet as its running really well and not giving me any trouble, nor does it get hot.
If you change the Y axis motor dont forget to order the dual shaft version unlike the X axis one that is single.
I will fit mine to my bigger x/y chassis when I get round to making it.

Ian

[crozza]

Hi All

Did did a speed test today on the X axis.
560mm per second no problem at all. Ran a full engrave of the entire 300 x 200 work space.

The motor ID number on my Nema 17 is 17H185H-04A.
Running at 8 micro steps at 1.8 amps.

[Gadroc]

What was the part number of the original stepper?

[baccus61]

Hi Guys,
Just thought I would write a bit of info on stepper motors for you guys. I don't know if you know any of it but it will be good for people who don't know.

Stepper motors are current driven not voltage driven like most motors and they can be run at around 20-25 times the voltage they are rated at BUT you can NEVER go over their rated amperage or you will burn them out.

When buying a stepper you generally try and source one rated at around 1.5 volts then to get good speed out of it run it at around 38-40 volts. Some manufacturers of stepper drivers run their motors at 120volts!

The more amperage the stepper is rated at the better power or holding torque they have. The higher the voltage the more speed - until it reaches it's limit and starts to lose steps and power. They have the most power at slow speed and lose it as the revs get higher. This is one of the reasons we gear down the smaller steppers to about 3:1 but using them for a very light laser head is ok if they are not geared down due to the low mass of the lens assembly. You only lose positional accuracy.

They (steppers) typically run at about 80 deg C so you will burn yourself on them if you touch them. This is normal!

The steppers you have are rated at 1.6 amps and your DSP might be putting out 1.0 amps so they will run cooler but you lose power and holding torque. For our application it isn't much of a problem. The other size stepper on their site is rated at 0.33 amps so the one you have is about 5 times more powerful so you have selected the right one for your situation. If you had the other one then you might only get 200mm/sec out of it before losing steps.

I hope this helps you somewhat.

There is a lot of information out there on stepper motors and it is worth the time to read some of it and understand how things work.

Rich.

[baccus61]

Hello Ian:
(Blah blah blah),
The feeling was so good! The original K40 can't handle vector cutting but raster engraving only. Plus, it's so slow and the Moshi was terrible (what a junk actually). But after the upgrade even the manufacturer were stunned with performance and asked me 'how to', ha..ha...

Great job!

Marco

I bet you felt good after showing them how to do it properly. Go to the top of the class, Marco.
Rich.

[Gadroc]

Nice write up there baccus61. Unfortunately I can't find any data sheets on the steppers which came with my machine. I've been pretty surprised with the performance of the stock ones compared to what other people are reporting. I'm wondering if I got lucky.