Recensione Anycubic Kobra Max -3Digital

Anycubic Kobra Max review

With a 40cm x 40cm heated print bed and a maximum print height of 45cm, the Anycubic Kobra Max belongs to the largest of the 3D printers currently on the market for home users. Aside from its physical size, this 3D printer has the ease of use common to all Anycubic devices. The combination of a dual-unit extruder and a Volcano hotend succeeds in delivering even larger volumes of print material to the silicon carbon (carbon glass) print bed.

Anycubic will announce five new 3D printers in the second quarter of 2022. One of them is the Anycubic Kobra Max. This huge 3D printer lives up to its name with its 15.75 x 15.75 x 17.72-inch build volume. (400 mm × 400 mm × 450 mm). In addition to its size, this 3D printer offers some special features. For example, as with the previous Vyper model, a load cell is used for automatic print bed leveling.

Our tests show that the Kobra Max is able to deliver reasonable print speeds and commensurate quality at the same time, when certain settings are adjusted to the job at hand. But at its price it's not just its physical size that leaves an impression. And due to its size, its power consumption is also relatively high.

At least in terms of size, the Anycubic Kobra Max is a direct successor to the Chiron, while the technology itself tends to be based on the new Anycubic Vyper model. Therefore, in the category of large volume 3D printers there is a newcomer with the latest technology in its ranks.

Specifications

It's not hard to distinguish the Vyper from the Kobra Max's predecessor, and aside from the size-related adjustments, there are few changes to this printer's basic design. However, the PEI coated spring steel build platform has been replaced with a silicon carbide coated glass build platform.

Anycubic Kobra Max
Underlying Technology FDM, FFF
3D print size limit 400 mm × 400 mm × 450 mm ≅ 72 L (1ft 3¾ in x 1ft 3¾ in x 1 '5 11/16 in, approx. 2 ½ cu ft)
Dimensions excl. power lead 80cm × 83cm × 72cm (2ft 7 ½ in x 2ft 8 11/16 in x 2ft 4 3/8 in)
Kinematics Prusa / Mendel XYZ calibration
Extruder Bowden dual gear extruder with a Volcano hotend
System board Microcontroller Trigorilla Pro A V1.0.4 Board HDSC hc32f460
Firmware on supplied test unit Anycubic Kobra Firmware (Marlin Derivate) GCode-Compatible
Stepper Motor Driver 1/256 step interpolation stepper driver with soldered pinheaders
Ports micro SD, USB Type B
Controller internal touchscreen (serial connect via USB)
Power supply internal 110V - 240V to 24V power supply
Manufacturer's website Anycubic

The large 3D printer is delivered in a suitably large cardboard box. Contains all the tools needed for assembly as well as some spare parts. While the Kobra Max hasn't been over-dismantled, you should take your time assembling. Due to the large size of this 3D printer, almost every single part is somewhat bulky and you should allow a total of one hour for assembly and initial setup. Since the frame is screwed to the base, it has two pendulum support stabilizers. To avoid twisting the frame, it is especially important to make sure these stabilizers are loosened before tightening the mounting screws. There are some open questions about the printer cable routing as Anycubic's mounting instructions are still not very accurate. Even with clear instructions as to which plug goes into which socket, our test group gives a decidedly messy impression.

The assembled printer weighs well over 20 kg (44 lbs), so you should decide where to place it before installing it. Due to the size of the Kobra Max, moving the unit even short distances is not that easy, especially since the printer over two and a half feet wide may have a hard time going through a normal door frame.

While it still looks relatively neat under the cover plates, this 3D printer doesn't have a good way to route cables to the print head and X-drive. The two wires of cable hang loosely on either side of the Kobra Max and the wire of the cable that goes to the print bed looks quite short. Also, when working on the back of the build plate, the cables don't seem to have the necessary slack for movement. Over time this could cause damage to the cables. There isn't even a conduit for cables connecting to the touchscreen. In summary, we would look for better cable routing for all cables coming from the base of the unit.

Cable ducting inside the base unit
Cable glands inside the base
Two strands of cables lead to the X axis
Two strands of cables lead to the X axis
The cable strand to the print bed is close to buckling

THE Mainboard

Trigorilla Pro A V1.0.4 board
Trigorilla Pro A V1.0.4 board

The Anycubic Trigorilla Pro A V1.0.4 card comes with minimal connectivity. Upgrade options for do-it-yourselfers simply aren't provided. It is simply not possible to determine exactly which stepper motor drivers are hidden behind the welding and cooling unit that are wrapped around them.

The microcontroller is a HDSC hc32f460. Its 32-bit chip with a Cortex-M4 CPU runs at 200 MHz and provides an abundance of computing power. To avoid overloading the components of Trigorilla system boards - the printer bed requires a high amperage - Kobra Max has its own external power control unit.

Structure

Two pendulum stabilizers ensure the much needed stability of this unit. As is commonly the case with current 3D printers, its moving parts run on a combination of V-groove aluminum extrusions and D-rollers. This rather rigidly configured solution shows its limitations as a direct consequence of the length of some profiles. While there is no lack of 40mm x 40mm (1 9/16 '' x 1 9/16 '') profiles implemented in the base, the 2020 20mm (13/16 '') aluminum extrusion for the printhead feels inappropriately flexible .

The print bed, on the other hand, seems particularly well stabilized. A total of 12 D-rollers run on two profiled rods. The only problem that arose was adjusting the settings to allow the wheels to rotate freely. In our test, the fixed row on the right side was first aligned with the rollers above the eccentric nuts, followed by the left. A challenge in doing this lies in the non-negligible thermal expansion of the printer bed. Even in theory, the large aluminum printer bed to which the Carborundum glass is attached will expand by nearly a millimeter when heated to 60 ° C (140 ° F). In the ten days that the 3D printer was made available to us for testing, we had to adjust our settings on several occasions.

The Z axis is driven by two motors and threaded spindles synchronized via a timing belt. The use of compression springs on the T-8 nuts ensures backlash-free operation of the belt.

Check the printer

Available settings during a print operation
Settings available when printing

Anycubic Kobra Max is driven from a touchscreen or via USB using applications such as Pronterface. The touchscreen menu is clearly structured. Numeric values ​​can be entered via a counter with +/- buttons or via a numeric entry field. The clear menu layout, however, doesn't offer many control options beyond standard, compliant bed leveling, preheat, and filament change. And while printing is in progress, only adjustments are available that govern print speed, temperature, fan speed, and the LEDs built into the printhead.

Missing is a smart tool for establishing the required Z axis offset and the ability to change the extrusion multiplier. It only works when connected to a computer.

Performance

Print bed

First layer print speed test
First layer print speed
Thermal image of the printer bed
Thermal image of the print bed

The silicon carbide coated printer bed is not exactly leveled as such, but the adhesion qualities are good once the automatic bed leveling process is complete and the Z axis offset adjustments are made. Carborundum glass is fixed here with six clamps on an aluminum plate with the heating element. In addition, the build plate has a thin thermal insulation on the underside.

The printer bed is heated via the 24 VDC power source and consumes up to 400 W. However, it takes approximately five minutes to warm up from approximately 20 ° C (68 ° F) to 60 ° C (140 ° F) due to the large affected area. The firmware allows up to 110 ° C (230 ° F), making it difficult for the Anycubic Kobra Max to process ABS. The thermal image shows a drop in temperature over a margin of about two inches around the edges. Otherwise, the heat distribution on this large print bed looks relatively even. We did not, however, cause any adhesion degradation along the edges. It is very likely that the temperature difference, measured by the Flir One Pro, is less than the actual temperature difference, as the surface emissivity was not measured on the apron.

Hotend and Extruder

A BMG-style extruder and Volcano hotend do a great job on the Anycubic Kobra Max. The approximately 45cm (one and a half foot) long PTFE tubes that supply the filament to the unit are barely noticeable in our print results. As is quite common for dual gear extruders, a whistle is heard with each retraction. The print head and overall structure of this model are not significantly different from those of the Anycubic Viper and the rather unusual process for automatic bed leveling is implemented here as well. When you lower the printhead nozzle to the individual contact points, a load cell determines the timing. What is noticeable with the Kobra, however, is a slight deviation from the specified parameters. This is due to the rather high flexibility of the X axis and the print bed. This x-axis flexibility is least pronounced at the edges of the print bed and is greatest in the center of the print bed. This results in a saddle-shaped distortion detected by the ABL sensor. However, we did not identify any issues during our rather short test period, apart from a little over and under extrusion in the respective areas of the first layer. The printhead is also equipped with a small LED light and two radial fans which are positioned next to the hotend and load cell.

The BMG clone can provide high flow rate in the extrusion test. Only at the required 20 mm³ / s (about ¾ in3 / s) does the filament flow stop. This provides a calculated maximum print speed of approximately 180mm / s (just over 7 inches / s) given an extrusion width of 0.044mm (44μm) and a layer height of 0.2mm (200μm) .

However, during printing, the back pressure in the nozzle increases. The first real problems become evident in our test scenario at speeds above 140 mm / s (5½ in / s). At a print speed of 150 mm / s (5.9 inches / s), the first holes appear in the printed test output. Given the potential size of Anycubic Kobra Max's printed output, faster print speeds seem somewhat desirable. An alternative approach to achieving faster print speeds would be to use a larger nozzle. Especially with large objects, using 0.6mm or 0.8mm nozzles could save a lot of time. Anycubic supplies only one 0.4mm Volcano nozzle.

Extrusion test
Extrusion test
Results of the extrusion test
Extrusion test results
Print speed test - First issues at just over 5.5 inches / s (140 mm / s)
Print Speed ​​Test - First problems at 140mm / s

Print quality

The micro-SD card that came with our test device includes a Cura profile that we used unmodified for our reference print quality testing procedures. Anycubic recommends using relatively fast print speeds up to 80mm / s (3.15in / s).

Robust results create a favorable impression of the device's embossing capability. Even with an angle of 70 ° there are no visible problems. There is some sign of stringing and blobs, but these are very limited. Even between thin walls and in the spaces between small needles, the plastic threads are barely noticeable. And finally, the molded gate and rotary knob turned out to be movable even though breaking small threads of molten plastic on one of them was somewhat difficult.

Regarding the dimensional accuracy, the maximum deviation measured was 0.08 mm (80 μm). That is to say, the extruder provides less plastic than the slicer assumed. This may also explain the slight sub-readings of our test measurements. Our test sample's adhesion to the print bed was excellent, and none of the corners showed any signs of lifting or wrapping.

In practice, this great 3D printer works flawlessly and there is hardly anything to find fault with other than a negligible under-extrusion. The Cura print profile works well and allows print quality and print speeds to reach very good performance levels.

Safety

Our review unit's temperature fault shutdown mechanism and thermal overload protection worked well in each case. The printer detects both shorted and disconnected sensor cables and turns off the corresponding heating elements as needed. When artificially heating or cooling the hotend or print bed, the 3D printer also cuts off power to the heating elements.

If it weren't for the noisy 500-watt power supply fan, the 3D printer could be very quiet. However, the demand-based ventilation system by far covers all other noises generated by the 3D printer. When this fan is not working, the Voltcraft SL-10 sound level meter measures a maximum volume of 48 dB (A) from a distance of one meter (~ 3.3 feet). As soon as the power supply fan is needed, the sound volume increases to approximately 57 dB (A). Due to the open design of the 3D printer, smells from melted plastic are dispersed throughout the room.

Power supply with fan
Power supply with fan

Electric consumption

The power consumption of the Anycubic Kobra Max can be relatively high, if you compare this 3D printer to smaller devices like the Artillery Genius Pro. We measured the power consumption with a Voltcraft SEM 6000 when printing a 3DBenchy. The power requirement for the print bed heated to 60 ° C (140 ° F) is approximately 230 W after the initial warm-up. Due to the size of the build plate, convection heat loss is quite high. To save energy, it is worth reducing the fan speed to cool an object or using the fans only when they are needed. Also, for many PLA prints the build plate temperature can be reduced by 10 oC after printing the first layer.

Power consumption measurement - Anycubic Kobra Max- 3D-Benchy (moving average and measured values)
Energy consumption measurement - Anycubic Kobra Max- 3D-Benchy (moving average and measured values)
Power consumption measurement - Anycubic Kobra Max- 3D-Benchy Energy Saving Settings (Moving Average and Measured Values) (Partial Measurement)
Energy consumption measurement - Anycubic Kobra Max- 3D-Benchy Energy saving settings (moving average and measured values) (Partial measurement)

In a later test using these power saving settings, the power consumption of the Kobra Max dropped by a whopping 100W and nearly 200W during the cool down period of around 4 minutes. Although the quality of the two 3D benchies almost never differs, the proposed energy saving settings require 140 watt hours less.

Verdict

The Anycubic Kobra Max - supplied for our testing by Anycubic

Due to its size, the Anycubic Kobra Max 3D printer is certainly not suitable for everyone. If you want to take full advantage of the capabilities of this 3D printer with its 400mm x 400mm (16in by 16in) print bed, you should aim to gain a solid understanding of the 3D printer and slicing software settings that come with the your device as these are many and varied. Small changes to the Cura profile can reduce print times for larger objects by days. Also be aware that prints that take advantage of the Anycubic Kobra Max's large volume printing capacity can take several days. Aside from the problems that can arise due to the size of the device, our tests of the Anycubic Kobra Max were convincing. From a quality standpoint, the results are in line with many other 3D printers.

If your projects require large quantities of parts, you can rely on the Anycubic Kobra Max. Our tests have shown that this 3D printer works consistently and delivers high quality results.

The high power consumption is probably our biggest criticism of the device. While some energy can be saved with the appropriate adjustments to the cutting profile, smaller printers are ultimately the right choice for smaller parts. If you need to print large parts faster, you should also consider other nozzle sizes. The 0.4mm nozzle installed in the Volcano hotend is universally considered an appropriate choice, but larger hole diameters and extrusion widths can greatly accelerate 3D printing, while the level of detail will often decrease only marginally.

Price and availability
Anycubic Kobra Max will be available for sale from the end of May.

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