If you have been to our website before you will notice that “It’s changed”, or better put “it’s changing”, If you think it’s hard to set up a Mendel, try relocating an e-commerce site! We will be spending some time readdressing broken links from the old server over the next few days, in the mean time all our picture files on the Reprap forum are pooched. To anyone who has linked to the eckertech.mybigcommerce.com test site. Big commerce doesn’t provide the facility to redirect that link to the new website so….. sorry, you will have to readdress your links. As of now the blog posts from the old website are inaccessible until we manage to transfer them to the new blog, sorry for the inconvenience. The new blog accepts reader comments so it will be much more convenient than the old one, which leads to the reason for the change.

When embarking on our Reprap journey a couple of years back our goal was just to make a Mendel print. That accomplished, we set our sights on improving the machine’s print quality and the overall mechanical performance of the machine. In the midst of this came the challenge for anyone with a working machine to print Mendel parts in order to propagate the species, and so we began selling printed parts on Ebay. We have now shipped over five hundred sets to many different countries, mostly Sells Mendel, and nearly One thousand hobbed bolts. We have always maintained that providing quality printed parts is our first priority. Secondly, born of our own frustrations with standard bolt hobbing methods we developed a better hobbed bolt, and began providing them in our parts sets to help our customers get started without having to endure that frustration.

As we noted on our previous website our goal is to become an outlet where budding Reprappers can come and get the products/services they need. We have grown slowly so that we do not over promise and under deliver. This new website is the next step in the growth of EckerTech Inc.

This new streamlined website allows for improved customer contact/care and a new suite of products. We now offer 3mm ABS plastic in a variety of colours, High Torque stepper motors, Pololu stepper boards, heat sinks and PLA bushings. With Ramps kits, hardware and assembled or DIY complete printer kits coming soon. As with our printed parts, our priority in building our product line is in quality and durability. The products listed on the new site have been thoroughly tested and run daily on our own machines.

We have been so busy trying to keep up with demand over the past few months there just hasn’t been time to update the blog…….. Sorry.

Running our machines 24 hours a day, brought with it vivid reminders of the true meaning of cheap. Breakdowns and failures. I have been dealing with machinery of varying type in varying shapes of disrepair for over thirty years and I have learned this lesson over and over again, cheap designs and cheap fixes make for a very frustrating and busy maintenance schedule. Cheaper may sound more inviting in the beginning but it invariably ends up costing more in the long run. Component failures, lower productivity, and of course lost product do to the aforementioned failures are the end result of cheaping out. This is good example:

Had we spent the extra $10.00 per unit on our original machines we would have ended up saving $150.00 in the long run, not to mention lost prints and many hours spent replacing burned out power supplies. We purchased our original power supplies from advice given on the Reprap forum, 250 watt minimum was the suggested standard. At the time of purchase the smallest ATX power supplies available were 350 watt, so that’s what we bought. We felt fairly confident that a 100 watt cushion would provide us with ample and dependable power supply in the long run……… Wrong! After several failures we began to realize that power consumption is relative to speed at which the machine is running, and Our Mendels are fast. I guess that people can only relate to their own experience and in hindsight the advice on the forum was coming from people printing in the 40mm/sec fill and 20mm/sec perimeter range. We were printing at 60/48 at the time. Seems the need for speed had taken us beyond the expertize of the experts on the forum.

On our Gen 3 machines we are now using twin 585 watt Orion ATX power supplies, one to run the machine and one for the heated bed. On our Ramps machines we are now using single Antec 650 watt true power ATX power supplies, not as much labeled power per machine but they are very well built and capable of handling heavy loads for extended periods, they are rather expensive but each machine only requires one so the cost per machine is similar.

Initial expense aside, since changing over in late summer we have processed over 500 lbs of ABS filament in round the clock production without a single power supply failure. In the course of the changeover we also transitioned our host program over from Reprap host to Repetier to accommodate a change in firmware from the official Reprap firmware to Marlin non Gen6. Using modest acceleration settings in Marlin we are now able to print up to 120mm/sec depending on resolution, which increases the power consumption once again. We are now limited by the ability of our extruder’s to melt the plastic.

All in all, changing all the machines over to the new power supplies did cost several hundred dollars, but well worth the expense in the long run. I doubt very much that we could have met our deadlines if not for the change.

At EckerTech, we are never satisfied with the status quo. Good enough is never good enough for us. As a group we strive for better, faster, smoother, and above all reliability. Inevitably, as a system is driven toward its limits, weaknesses and design faults become apparent as components begin to break.

The first major mechanical problem we encountered in our Mendel with increased printing speed was an issue of reliability in the Y axis drive. The design of the original   motor bracket left the drive pulley extended beyond the end of the standard motor shaft and the drive belt straddling the tip of the shaft. While this positioning was noted early on it didn’t cause much in the way of problems until print speeds exceeded 50 mm/sec at which point the very odd occurrence of a broken drive pulley became annoyingly frequent. Notably the pulleys would crack and break off at the tip of the motor shaft leaving the belt to ride over the edge and fall off.

A secondary problem was also noted with the increased speed. As the drive belt teeth stepped back and forth over the 624 idler bearings the uneven surface began setting up strong harmonic vibrations in the belt causing it to fan wildly. At certain frequencies the upper and lower segments of the belt began to sound like a small bird in flight and at times nearly touched.

To resolve the problems we made the following design changes.

Y – Motor bracket – Download

As shown in the following diagram, we reduced the thickness of the motor mounting area to allow the motor shaft to extend fully into the pulley. This solved the broken pulley problem. After printing hundreds of hours on three different machines we haven’t had a single pulley failure. Included in the Y-Motor bracket update is a mounting point/shelf for opto end brackets or micro switches.

3D – Rendering

Actual Print

624 Bearing Pulley – Download

To facilitate a better 180 degree turnaround at the idler bracket, and smooth the belt travel at high speeds a new pulley was designed based upon the Z-Axis pulleys, with the addition of capture points for 4 – 624 bearings (2 per pulley).  This redesign, virtually eliminated any belt fanning problems and prolonged the life of metal strapped belts.

3D – Rendering

Actual Print

Y – Idler Bracket – Download

To prevent any deflection caused by mounting the pulley at a single point, we have redesigned the Y-Idler bracket into 2 mirrored blocks. This new design distributes the belt forces evenly across the pulley, eliminating any deflection and better supporting quick direction changes in the Y-Axis.

3D – Rendering

Actual Print

This is a print of Wade’s Extruder in blue ABS using pololu steppers on a gen 3 motherboard.

In this video we are printing at 55mm/s but we can now print successfully at 70mm/s.

We use java 5 update 22 on windows xp. Skeinforge from June 29, 2010 and the nightly build from October 18, 2010 for RepRap host.

To prevent the bearings from ending up on the threads of some M8 bolts we have come up with a very simple design change, reverse the bolt. By reversing the bolt installation and moving the area of the bolt that gets hobbed we can avoid the bearings resting on the bolt threads.

The bolt is now inserted from the motor side of the extruder. We use 2 jam nuts, 1 washer and 1 standard nut to squeeze the bolt, extruder block and gear together.

For installation instructions, see Alternate Wade’s Extruder Hobbed Bolt Installation.

This video displays the gripping power of our bolt.

It can literally pickup a Mendel without shredding or breaking the filament.

After testing several nozzle sizes and thousands of combinations in Skeinforge we settled on a .406mm nozzle instead of the standard .5mm nozzle.

The results are very evident from the picture on the right. Along with enchanced definition, which is particularly evident on prints with small spaces, there is a definite improvement in structural integrity.

Prior to the smaller nozzle size all of the gears we printed with a .5mm nozzle tore apart after printing for a short time (on average 68 hours of printing). Our gears now last much longer we have logged well over 1,500 hours and counting on our Black Mendel without replacing a single gear or pulley.

To get this kind of quality we use the following:

• .406mm nozzle
• Pololu stepper boards
• Gen3 Motherboard
• Microstepping
• Java 5 update 22 on windows xp
• Skeinforge from June 29, 2010
• The nightly build from October 18, 2010 for RepRap host