Two of the most common 3D printer systems used today are CoreXY and H-bot. What is the difference between these two systems? Which one is better? In this CoreXY vs H-Bot guide, we go through an overview of the two 3D printer systems, their advantages and drawbacks and everything you should know about them. Read on.
The main difference between CoreXY and H-Bot 3D systems is the way they work.
In traditional Cartesian 3D printers, the printhead moves along the X-axis while the printhead moves along the Y-axis. On the other hand, in both CoreXY and H-Bot 3D printer systems, the print head moves along both the X and Y axes but the printbed does not.
What is the difference between CoreXY and H-Bot systems?
The main difference between CoreXY and H-Bot 3D printers has to do with the timing belts.
CoreXY 3D printers have two timing belts while H-Bot 3D printers have a single belt. Having two belts makes CoreXY 3d printers less wobbly during a print job. As a result, the machines print models faster and more accurate than their H-Bot counterparts.
To better understand how the CoreXY system works, watch the video below:
With CoreXY printers, both belts are attached to the violet objects at both ends.
The red and orange driving pulleys determine the direction that the violet objects will move along the X and Y axes. The red belt connects the orange pulley with the yellow pulleys while the black belt connects the red pulley with the pink pulleys.
Here are the movements realized depending on the rotations of the pulleys:
- The violet object moves diagonally when only one drive pulley is rotating
- The violet object moves in the Y axis when the red and orange pulleys are rotating at equal speed in the same direction
- The violet object moves in the X axis when the red and orange pulley are rotating and equal speed in different directions
The green line represents the direction of a point on the object.
Here is a video showing how the H-Bot 3D system works:
As you can see, the orange object moves along the X and Y axes, depending on the rotation of the green and pink pulleys.
One important thing to note about the H-Bot design is that a part of the black timing belt runs through the orange object while the other part is attached on it.
Here are the possible movements of the orange object:
- The object moves along the Y-axis if the green and pink driving pulleys rotate at equal speeds in the same direction
- The object moves along the X axis when the green and pink pulleys rotate at equal speeds in opposite directions
- The object moves diagonally when one pulley rotates.
The green line represents the direction of a point on the object.
CoreXY vs H-Bot: Which System Should You Choose When Building a 3D Printer?
Looking at the two systems, the H-Bot design seems smoother and more effective than the CoreXY design since the latter has more pulleys and belts distributed on different levels.
However, when you check the size of the printer and compare preciseness, the CoreXY are clearly ahead. This explains why many 3D printer manufacturers are coming up with CoreXY 3D printers.
Both CoreXY and H-Bot systems use the Cartesian coordinate system.
CoreXY systems have two stepper motors for the X and Y axes, while H-Bot systems only have a single motor for each of the three axes. The motors allow higher acceleration, which means low inertia. Moreover, their positioning accuracy ensure there are no guide errors.
H-Bot systems are similar to CoreXY systems in the area of the drive. However, instead of two short belts like the CoreXY system has, the H-Bot system has one very long belt.
The long belt of the H-Bot system mean leads to reduced print quality and more likelihood of errors. Moreover, if the belts and axes of the H-Bot system are not perfectly aligned, the system’s lifespan will be negatively impacted.
Now let’s look at the differences between the CoreXY and H-Bot systems
CoreXY vs H-Bot Systems: What Are the Differences?
The CoreXY uses the Cartesian coordinate system and features a compact, square design. This system is different from a Prusa in that the printing bed moves only on the vertical Z-axis. However, the print head of the system moves along both the X and Y axes.
When compared to the H-Bot system, the latter has a longer timing belt and a much larger pulley system. The longer belt reduces excessive torque and, consequently, degradation of the belts and the printer in general. H-Bot systems are also designed in the Cartesian system.
Most CoreXY models come in an open design. However, high-end models may have an enclosure. The system’s print head is driven by two timing belts connected to a stepper. On the other hand, the H-Bot system is only driven by one timing belt.
The movement of the print head depends on the number of pulleys moving as well as their direction.
Advantages of CoreXY Systems
Unlike other Cartesian design systems, the CoreXY system has two stepper motors that control the axis. Moreover, the belt are arranged in a special way to enable the print head to move in both the X and Y axes.
This design makes the CoreXY system advantageous in the following ways:
- Fast printing speeds
- High precision
- When compared to the H-Bot system, it prevents unwanted torque in the area of the frame
In normal 3D printer systems, a moveable portal is usually attached to the printing bed or each stepper motor. As a result, during the printing process, the portals usually move back and forth. This makes the printer vibrate a lot and leads to faster wear and tear.
On the other hand, the stepper motors of the CoreXY system are firmly fixed. Therefore, there is little vibration during the printing process, which means your models will come out precise and with smooth outer surface.
Moreover, the print bed can move along the Z axis. This, therefore, means that the printer can produce models of the same size without the need of having a large build volume. This is one feature that the CoreXY system shares with the H-Bot system.
The tool head of the CoreXY printer moves along both the X and Y axis, access the whole building board.
The straps of a CoreXY system can be quite difficult to deal with for beginners. For instance, if they are not correctly tensioned or aligned, they can lead to various problems.
If the belt is too loose, the printer’s precision will be compromised. On the other hand, if it is too tight, the printer will wear faster. Other malfunctions can also occur when the belt is not properly tensioned.
The timing belts play a critical role in a CoreXY design. For instance, if they are made of cheap material, they will wear out faster, making the printer lose precision after a short time.
Drawbacks of CoreXY System
Some of the disadvantages of the CoreXY system are:
- The systems generally require longer belts
- Requires many deflection rollers
- More complex to operate
However, the problem of improperly tensioned belts is not unique to CoreXY 3D printers. Other printers also have the same problems when fitted with timing belts that are either too loose or too tight.
The frame of CoreXY 3D printers is relatively stable. However, if it is not assembled to be perfectly square, it can lead to precision inaccuracies. To fix this problem, use corner brackets to keep the CoreXY printer squares fixed.
Overall, the CoreXY printer set up is easier and more compact. These machines print faster and more accurate prints.
Advantages of H-Bot Systems
The H-Bot system looks elegant. However, the printer usually have precision problems, except for systems with high tolerances.
As is the case with CoreXY 3D printers, the H-Bot system uses a pair of stepper motors that are joined together. Therefore, it also generates movement in the X and Y axis.
However, one drawback of the H-Bot system is that if the axles and belts are not properly aligned, additional torque is generated. The belts cannot be perfectly aligned.
With additional torque generated, the printer may jam and the print quality is compromised. This effect can be reduced but you need to know quite how to handle alignment issues.
The advantages of the H-Bot system include:
- Theoretically, it can achieve high-precision printing
- Has only one timing belt
The H-Bot system has two motors that move the timing belt. The belt is attached to the carriage and moves on a guide along a single axis, while guided by pulleys.
Two more guiding attachments allow the belt to move in the orthogonal direction.
You can configure H-Bots to work as X*-stage portals but without the disadvantages. The H-bot can be planned to move together with other parts. This functionality can enable different applications.
Some of the applications of H-Bot systems include point-to-point positioning, plannable or 3D cutting, material filling and applications, selection of location, and more.
The H-Bot system is also affordable. For example, it uses less expensive sprockets or pulleys instead of threaded spindles. The belts are also cheaper than linear motors or lead screws. This reduces the overall cost of the system.
The axes of the H-Bot system are not stacked on top of each other, as is in the case with the CoreXY system. Therefore, the complexity and total weight of the system is reduced as well. This reduction helps to save costs.
The low weight of the system means that smaller motors can also be dimensioned. This helps to increase the throughput while the less mass also accelerates the system.
The two stepper motors share the same load, which is relatively balanced. You can replace the threaded spindles with the belt drives to reduce friction in the system.
You can customize the H-Bot system and enlarge or reduce the working areas designing on your requirements. You can also change the diameter of the drive pulley to adjust the accuracy and speed of the system.
Finally, you can use cheaper rotary motors with this system.
Drawbacks of the H-Bot System
- The quality of prints can reduce due to additional torque
- Requires perfect alignment
- The belt is very long
The main issue with the H-Bot system is that its movement requires precise XY coordinates. Moreover, since the two stepper motors are joined together, you have to consider additional safety aspects for limit values. To stop the systems when a limit value is reached, the two motors have to be braked. Since the timing belt is flexible, it can cause a load position error due when the two motors are braked.
CoreXY vs H-Bot: Conclusion
The CoreXY solves the additional torque problems that the H-Bot system has. The open-source printer system has a two-axis linier motion implementation and a more moveable platform. Both motors used in this system are attached to the frame.
However, both systems have fixed motors and their print heads can move anywhere along the X and Y axes. Both units are focused on reducing wear and fast printing speeds.