3D Printing - "It's all about design and quality output. Not how fast the printer can run."
Delta Construction Error
The accuracy of the Delta printer is very good. It prints with far less “ringing” than my Cartesian printer. Very impressive smoothness of the outer printed shell. The Delta prints much faster than the Cartesian. I have mentioned that before. It’s all about the mass and inertia thing. Less weight moving means faster and smoother printing.
On my Delta, the print surface is 200mm in diameter. The printing area is claimed in writing to be 180mm diameter. That’s 10mm short of the outside edge. The measured maximum round printing area is only 140mm when built following the kit instructions. There is a design problem with the Delta I own.
I discovered the problem when I could not print a 120 x120mm box with a corner diagonal dimension near 155mm flat on the bed of the printer. An axis trolley hits the stop at the bottom of its column.
The reality is the available print area is NOT a round circle. The tern "diameter" led me to believe the 180mm printable area was round. Not true. It's a "puffed"-up delta area. The corners of this delta do reach to within 10mm of the edge but the sides are 30mm from the edge. (see pictures) The effective ROUND printing area is ~140mm
I first thought I need to lower all three of the existing side rails by about 35-40mm. That requires loosening all the rail and end stop bolts and sliding them all down the proper distance. Then I may get the 180mm claimed base print area without hitting the bottom stops. I am concerned as the print head already hits the axis drive belts as it is now. It would be disastrous if the print area is expanded more.
The software print limit needs to be set to 140mm (round) printable area. The largest Square that can be printed is 99mm on a side.
Update 11/23/16 - ANYCUBIC has provided a SOLUTION.
But for now, it sure does print nicely in its 140mm “sweet zone” in the middle. The overall diameter of the print bed is marketing hyperbole. The important information is the size of the printable area. Depending on the printer design or in this case, an engineering decision, it can be far less than the bed diameter.
It can be noted as the Z height increases off the bed, the trolley can use the gained space from the stop and widen the print zone above the base without hitting the stop.
I had a bigger (300mm) version of a delta printer on my desire list but it was three times the cost of the 180/200mm version I chose. It’s claimed print area is the same 300mm as its base diameter. I assume its printing area is also a puffed delta.
No big deal. The Cartesian can do the bigger projects and the knowledge from using, and nice printing of the Delta is an excellent experience. Just what I was looking for with the costs involved.
Now that I am “smarter” about Delta style printers I can see the better geometry design features in the larger machine I was investigating. It has much longer arms to the print head. Proportionally more than would be required just because of the larger print area. The outer edge of the print area is not close to the corner towers. Much better design thinking and print surface positioning.
There is a big difference in sound level between my two printers. The Cartesian is (now) almost silent in its operation. It has become quitter the more it has run. The Delta has significant whine as it is operating. It’s too soon to say it may quite down with use. The linear glides are not the noise. It is the constant high speed operation of the stepper motors but it seems mostly to be coming from the extruder. Slowing the movement may abate the noise level of the whining, but then that is losing the advantage of the high-speed movement the Delta can manage.
It’s the old adage, “You pays your money and make your choice”. The more you want or need, the more it is going to cost. Right now, I have all I need and I am not complaining. Just sharing the knowledge gained from hands-on experience.