CR-7 3D printer

Introduction

The CR-7 is a low cost 3D printer made by Creality 3D with a Ormerod Design. We got ours from [ EastMachinery] (a Chinese online retailer. There are several offers for the same machine and I believe that we took this one. It took about a week to arrive in Switzerland and we got the full packaging list. Instructions were found in an include mini-SD card inserted into a USB adaptor. The manuals are in English and there are also videos.

There are several vendors that offer Ormerod models, but its inventors inventor's shop is closed (as of March 2016).

Specifications

• 15cm x 13cm build platform
• No heated bed, a removable sheet of plastic (what kind ? ) is included
• The extruder is a "Bowden type", it the motor is removed from the hotend.

Assembly and configuration

Assembly

Most of the assembly was done by 2 unexperienced students during a 3D printing hack day at University of Geneva. On another day, I then tightened the assembly and adjusted a few angles since it is important and on a third day a student calibrated the printbed.

Overall, assembly is fairly easy (compared to some other printers)

Software installation

• A driver needs to be installed (same as for the Felix printers), i.e. on Windows for the FT232 serial to USB chip.
• The printer can be used with repetierhost and the setup is easy, i.e. define a new printer, then copy the various settings.

First impressions

I did the first prints with a semi-transparent PLA that is about three years old (kept in the open, i.e. outside a sealed plastic bag).

The first print (a little duck) worked more or less. The second one (cat on Lego) was ripped off the print bed, the third one (Cat on Lego) was printed on glue. It has ugly cylinders underneath. Printing them slowlier and with a better plastic should solve the problem.

Recommendations

• Print contours slowly
• Use glue (e.g. Pritt Power Stick) to make objects stick
• Heat plastic somewhat more than with a recent mid or high-end printer.