Stoyanoff,
My design may be better in regard to some aspects but is definitely worse on others, in which your design is better. As everything in life, there are pros and cons in each choice. My design is better in precision and speed than a stepper and belt design, but is much more expensive, difficult to calibrate and heavier.
Kjelt,
This approach is a result of a combination of factors. My table has roughly 1x1.5 meters in size, it is very big, table alone have around 90-100kg. This is due the particularities I need for my machine. This whole pnp business, as I see it, is focused towards high speed in medium and high production volumes. This is why we see components on feeders and those are the kind of machines designed and optimized by big players in industry. But this is not good for low volume and prototyping, and everyone who asked quotations from PCBA for 10 pcs, knows it. This is also my business, designing many different products, prototyping them in 5-10 pcs and then low production batches, up 1000 pcs. For me is critical to have a fast machine setup and possible offline setup. I cannot spend an entire day setting up a machine for 100 unique components then run the machine for 10 minutes to produce a test batch. I need that machine offline and loaded up in less than 30 minutes. Fastest I can think of is with cut tapes and some kind of standard fixtures. Not feeders. Maybe only on very common components like 100nf and that feeder stays on the machine. Cut tapes are most common when we are talking about prototyping, it is not economically feasible to buy full reels or pay re-reeling service only for 10-20 components. This is why I need big XY space, for many cut tapes and trays.
And that comes to your question about 45 degrees. That 1.5 meters X support has to be very solid to avoid deflection. The profile has 2 stainless steels bars inserted on sides. The carriage balls run on those bars when traveling. If I would placed the profile horizontally, it deflects in the middle with approx. 0.2-0.3mm only due to its own weight, not counting the head weight. If I would place it vertically, it bends and it induces oscillations when travelling on Y axis, because it is quite flexible in the direction of travel. That is why I placed it at 45 degrees, to obtain stiffness in both directions. The only other way was to use another profile type, square, but that one would have been much heavier, and this is not good for Y drive elements, supports and performance.
SimonD,
I do not have at this moment total costs, they will be accounted only at the project end. But I can give you some price examples for most important components:
-ballscrews (plus end supports and motor connector) are TBI, around $750 plus $250 shipping from China
-Panasonic minas a6 400w servos, drivers and cables for both axis, around $1000, also from China. From european distributor, one motor alone was quoted at 700 eur.
-precision aluminium table 1x1.5 meters plus raw aluminium material for manufacturing parts: $800
Then comes the interesting part of fitting all together. If you do not have a mechanical workshop at your fingertips and you don't know how to use it, prepare to spend a lot in designing and manufacturing unique mechanical parts. This is also valid for every other task which you have to put others to do it if you don't know how to do it yourself. Calibrating mechanics, configuring servos, vibration analysis, driver hardware and firmware design, optical systems design, pneumatics, integration with software, etc....
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