T-Shirt Forums banner

1 - 9 of 9 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter #1
Before I begin my self-build DTG, I have decided to run through a few things first to ideally get the most beneficial build.

There is no donor machine for the final build chosen yet, so I'm under no obligation for a specific model.

My initial aim here is to build a simple machine first to get all of the errors I will be making along the way sorted, then to build an A3 machine with 4 colour white with a rip (Multi Rip looks like it can handle the job well, pricey but if it works!!).

My 'play' machine is an old Epson C40UX I picked up for £2.20 in working condition. Not an ideal candidate, but for pulling apart and getting to grips with the whole project before moving up, it will most likely do ok.

Ok, after reading through the vast knowledge on this forum, I couldn't help but notice that the pf motor is a huge issue for most people.

Would it not be an easier job to modify the whole print assembly to a gantry style, rather than a bed feed? This overcomes two problems;

1. The bed weight. This is obviously very important as the bed weight not only contains the adjustable platen, but also the majority of the build weight.

2. To print other garments the weight will be different for heavier material amounts such as hooded tops. Let's say that we were to print jeans, a standard pair of jeans weighs in at just over 1.2Kg, the pf couldn't handle this for too long if at all with the bed, platen, adjustable table and garment.

The printer assembly itself will always weigh the same.

That being said if the best build option really is the bed/platen feed, can we not get this powered by stepper motors on some sort of screw gearing like CNC mills? It should take the load weight off the motor and a higher torque stepper won't (shouldn't) burn out.

Your thoughts?
 

·
Registered
Joined
·
1,235 Posts
Darren,

I thought about a gantry style printer at first. I haven't seen anyone do it here so if you do I would definitely like to see your success. The problem I see with it is that you will have to mount the power supply and controller on the printer. It will have to move with it... or you will have to extend all the wires and flat cable... Not an inexpensive venture.

If you are sincere in trying to understand the error issues, I suggest the Workforce 1100 as an entry level printer. It will print CYMK and has the dreaded PF issues.

Bob ?;O)
 

·
Registered
Joined
·
8 Posts
Discussion Starter #3
Hi Bob, thanks for the reply. I've run into something of a snag in the preliminary design; ultimately the whole carriage will be covered in the final build, but having sat and drawn some basic sketches a substantial flaw has presented itself.

With the gantry style machine, the carriage would have to remain open if A) you wanted to keep the footprint of the machine small and B) you were to be able to remove the printed product.

This is not to say that it isn't do-able, in fact if I were to leave the final build open I wouldn't be typing now, however with a covered build it complicates the whole process somewhat.

To be able to add and remove the garment, a sliding bed would have to be built anyway so to facilitate the removal of the platen.

This raises a question or two for me. If I have to build both, why bother building the gantry? Should I just put the extra effort into sorting the drive problem instead, and have a moving bed like everybody else seems to have?

Initially, aside from the weight issue, I can't see many more benefits to a gantry style setup with the exception of printing multiples in a row. It should give much better registration, however I can also foresee carriage return issues for printing on darks.

Tell me, what would be the problem in replacing a like-for-like motor with a higher torque value? Are there specific tolerences or timing that can only be achieved with the Epson native motors?

With regard to the issues you put forth in your reply; the power supply and controller would be in a fixed position and the connectors to board extended for the length of the gantry movement +3 inches. The same for the other connected items.

These can then be housed in flat chain casing such as with CNC mills to both protect and retain their shape. They would of course need to be housed on the right of the machine (or left depending on which way you look at it!), so that it wouldn't get in the way and would be able to travel the whole gantry distance without fouling.

The drive would be housed on the opposide side, and in a similar configuration.

However that said, having weighed a printer (a basic home job) I feel that the motors will still burn out under stress.

After typing this I feel that the best (and not easiest) way forward is to change the drive to one more suited to the task.

I've built several CNC mills in the past (hence my continual reference to them) which can handle weights upto and including 20kg so the motors arent a problem, however they are MP controlled, which until I know a little bit more about how printers work could be a huge step to get over.

Anybody got any information on the motors and why we can't swap them to steppers. Are they timed? Are they torque specific?

My aim here isn't to build a machine as cheaply as I can, more to build one as stable as I can with little in the way of breakdowns.

I feel it important here to mention that I'm not doing this for financial gain either, just a project so I can say 'I've built one of those!' and then it will be donated to my local community centre.
 

·
Registered
Joined
·
232 Posts
The motors are plain DC motors controlled with PWM logic, much cheaper and more accurate with the use of optical encoders. I suggest to stay with the encoders.
In my printer the PF motor is a 48V/80watts dc motor, if you just add a bigger motor you will probably fry the bridge chip (there are two of these mounted on the heatsink) or you can add a cooling system for the chips and gain some extra power output...but its risky imho.
Things must be changed on the PF motor circuit,If you are comfortable with this electronic mod then go for it!
 

·
Registered
Joined
·
8 Posts
Discussion Starter #5
Hi Simon, thanks for the reply.

So if your motor then is a .10 HP motor running at 48v, do you know what RPM it runs at under load?
 

·
Registered
Joined
·
232 Posts
I dont know its speed under load, as long as you go servo (with encoder) then the circuit will give pulses in order to read what is supposed to read from the encoder, i guess that if you install a stronger motor with the same speed there will be no big problems.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #7
I was just trying to work out the torque.

I'm picking up my 'toy' printer tomorrow so I'll be able to pull things apart and see how things are organised a little better rather than just piecing it together in my head.

I think at this point though, the more important aim is to lighten the platen and strengthen the drive. There is much give and take but the platen design is the most valuable aspect. With an ergonomic and lightweight design, the weight is moved from the drive and the useability of the machine is enhanced.

An adjustable bed is a must, so is a platen (duh!), but why does the bed have to move with the platen?

I admit the whole thing moving would be the easiest and cheapest answer, but an all-in-one bed, drive and housing with only the platen moving would improve the entire motor burnout problem.

Anyhow, just thinking out loud so to speak. I'll report back when I have pulled my poor little epson c40ux to pieces.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #8
Ok I've had a look at the printer in the nude so to speak and everything is fairly simple in its operation, however I can see that there are some parts which will need a fair degree of precision for reliable operation so I'm going to build another CNC router so I can make the parts up properly without double sided sticky tape and a washing up liquid bottle.

Back soon.
 
1 - 9 of 9 Posts
Top