Extrusion Quality - Mystery issue resolved !

Summary

この動画スクリプトでは、高品質な3Dプリンティングの理論と実際の課題について解説されています。特に、ハイエンドマシンで表面品質を維持する困難さについて焦点を当てています。スクリプトでは、時間の管理、ノズルの位置、および樹脂の量の排出が表面品質に影響を与える可能性があることが示されています。また、Extruderの精度が重要であることが強調されており、Bowden設置と直接駆動Extruderの違いも検証されています。最後に、改善されたExtruder歯車や平面ベアリングを使用した実験が行われ、それらが表面品質にどのように影響するかが詳細に説明されています。

Takeaways

• 🔍 品質の良い印刷の理論は、適切な量のプラスチックを適切な場所とタイミングで提供することです。
• 💡 高級機で高品質の印刷面を実現するのが難しい理由は、多くの要因が関与しているからです。
• 🌟 照明条件は、3Dプリンティングで作られた部品の外観に大きな影響を与えることができます。
• 📊 印刷品質の問題は、時序、ノズル位置、Z軸の揺れ、プラスチックの排出量のいずれかの要因による可能性があります。
• 🔧 時序の問題は、ソフトウェア、エクストラハーサのモーター、XおよびYの動きのタイミングによって管理されます。
• 🎯 ノズルの位置の問題は、XまたはY軸の位置、安定性、およびZ軸の揺れに関連する可能性があります。
• 🚀 ボウルデンアダプターを使用したことで、非常に高品質の印刷が得られました。これは、直接駆動エクストラハーサの過剰な直接性を示唆しています。
• 🔩 エクストラハーサのシステムを分解し、正しい根本原因を正確に特定するために、個々の要素を調査する必要があります。
• 📐 歯車や軸の精度は、エクストラハーサシステムの印刷品質に直接影響を与えるため、精密な部品が必要です。
• 🔄 フィラメントの品質と直径の一致も、エクストラハーサシステムの精度に影響を与えるため、品質の高いフィラメントを使用することが重要です。
• 🛠️ イドラーギアや軸の配置が適切でない場合、フィラメントの位置が変わり、印刷品質に影響を与える可能性があります。

Q & A

高品質の印刷を実現するために必要な要素は何ですか？

高品質の印刷を実現するためには、適切な量のプラスチックを正確な場所とタイミングで供給することが重要です。

なぜ高級機でも表面品質を向上させることが難しいのですか？

高級機でも表面品質を向上させることが難しいのは、印刷機のタイミング、ノズルの位置、Z軸の揺れ、プラスチックの供給量など、多くの要因が関係しているからです。これらの要因を完全にコントロールすることは困難であり、運要素も一定の影響を与えるためです。

どのような設定がFDM印刷において最悪の照明条件を作り出しますか？

FDM印刷において最悪の照明条件は、頂部から尖锐な光が当たる状況を作り出します。これにより、レイヤーの積み重ね方や不規則な表面が明らかに見えてしまいます。

Bowden方式の印刷機がどのような利点を持ちますか？

Bowden方式の印刷機は、長いチューブが使用されるため、ノズル内のプラスチックの圧力が安定し、表面品質が向上することが期待できます。しかし、再tractionや圧力の調整が必要なため、調整が難しい場合があります。

エクストラダーの精密度が表面品質に与える影響は何ですか？

エクストラダーの精密度が表面品質に与える影響は大きいです。エクストラダーの歯車や軸の精度が不足していると、プラスチックの供給量にばらつきが生じ、表面に不規則なパターンが現れる可能性があります。

製造公差がエクストラダーの性能に与える影響は何ですか？

製造公差がエクストラダーの性能に大きな影響を与えます。歯車のHub gearの軸へのオフセットやフィラメントの直径の变化など、わずかな公差もレイヤーの厚さや幅に影響を与え、最終的な表面品質に大きな違いをもたらす可能性があります。

Z軸の揺れが原因となっている場合、どのような症状が見られますか？

Z軸の揺れが原因となっている場合、印刷物の表面に一定の間隔で繰り返し出现的する異常なパターンが見られます。これは、Z軸の揺れがフィラメントの供給位置に影響を与え、連続したレイヤーに同じエラーが現れることを意味します。

3Dプリンタのエクストラダーシステムを改善するためにどのようなアプローチを取ることができますか？

エクストラダーシステムを改善するためには、歯車や軸の精度を向上させること、製造公差を緩和すること、またエクストラダーの設計を最適化することが有効です。また、Bowden方式のシステムと比較して、直接駆動のエクストラダーの利点と課題を検討し、適切な方法を選択することも重要です。

なぜエクストラダーの歯車や軸が表面品質に影響を与えるのですか？

エクストラダーの歯車や軸が表面品質に影響を与えるのは、これらの部品の精度がプラスチックの供給量に直接影響を与えるからです。歯車や軸の歪みや軸の回転中心からのずれが、プラスチックの流量を変動させ、最終的に表面に不規則なパターンを生み出すことがあります。

どのようにしてエクストラダーの精度を向上させることができますか？

エクストラダーの精度を向上させるためには、高精度な部品を使用することが効果的です。また、エクストラダーの設計を改善し、歯車や軸の一体化、軸の支えを強化することが役立ちます。さらに、製造プロセスを改善して公差を減らすことで、エクストラダーの全体的な精度を向上させることができます。

エクストラダーの調整において、PIDチューニングとは何ですか？

PIDチューニングは、エクストラダーのホットエンドの温度制御を最適化するプロセスです。PID（比例・積分・微分）コントローラーは、温度エラーを最小限に抑えるために、加热期、保温期、および冷却期の時間を調整します。これにより、プラスチックの熔融状態を安定させ、表面品質を向上させることができます。

エクストラダーシステムのトラブルシューティングにおいて、フィラメントの品質はどのよう影響を与えるのですか？

エクストラダーシステムのトラブルシューティングにおいて、フィラメントの品質は重要な要素です。フィラメントの直径が均一でない場合や、品質が低い場合は、流量の変化を引き起こし、表面品質に影響を与える可能性があります。したがって、高品質なフィラメントを選択し、管理することで、エクストラダーシステムのトラブルシューティングが容易になります。

Outlines

00:00

🖨️ 印刷品質の謎

高品質な印刷の背後にある理論は単純であり、適切な量のプラスチックを適切な場所に、適切なタイミングで供給することです。しかし、高価な機械でもPrusaやよく調整されたEnder 3と同等の表面品質を実現するのが難しい理由を探ります。FDM印刷のための最悪の照明条件を使用して、層の積み重ねが醜いことを露呈します。高価なプリンターの一部で見られる表面品質の問題の原因を探求し、ソフトウェアのタイミング、ノズルの位置、エクストルーダーの圧力など、可能性のある原因を分析します。バーズモードでの印刷とX、Yガントリーの位置合わせの検証、Z軸のウォブル問題への対処方法など、品質問題の解決に向けた探求を始めます。

05:02

🔍 エクストルーダーシステムの分析

エクストルーダーシステムを細分化して、品質問題の根本原因を特定します。ステッパードライバーからフィラメントを押し出す一連の部品まで、システムの各要素を詳細に検証します。以前のボーデンプリントの成功から、ステッパードライバー、モーター、フィラメント、ホットエンドを問題の原因から除外し、システムの他の部分に焦点を当てます。一つずつ変数を変えながらのテストを通じて、表面品質に影響を与えない要因を排除し、BMGクローンのエクストルーダーギアへの変更が表面テクスチャの向上につながることを発見します。

10:03

🎯 精度問題の特定

ハブギアの軸ずれがエクストルーダーの精度に大きな影響を与えることを発見します。製造公差によってハブギアが軸からずれ、これが押し出されるプラスチックの量に影響を与えることが明らかになりました。ハブギアのわずかな軸ずれでも、押し出されるフィラメントの量に大きな違いが生じ、これが表面品質に影響を与えることをシミュレーションを通じて確認します。この発見は、エクストルーダーの精度が3D印刷の品質に非常に重要であることを示しています。

15:04

🛠️ ソリューションの模索

金属ギアの軸ずれを解決するために、さまざまな改良策を試みますが、問題は依然として残ります。プラスチックギアにも同様の軸ずれがあり、これが品質問題の一因であることに気づきます。Bontechから新しいシャフトを試すものの、依然として問題は解決せず、物理的なギアの精度が根本的な問題であることが明らかになります。新しい、より精密なギアの導入とそのテストを経て、表面品質における改善を観察しますが、完全な解決には至りません。

20:05

🔬 精密なエクストルーダーの重要性

エクストルーダーの精度が3D印刷品質に極めて重要であることを再確認し、フィラメントの製造公差も品質に大きく影響することを指摘します。精密なエクストルーダーシステムを構築するためには、より良いコンポーネントの選択が重要であること、また、精度の高いフィラメントを選択することの重要性を強調します。改良されたダイレクトドライブ構成の下で、Bowden方式に近い品質が得られたと述べ、最終的に、エクストルーダーの精度を向上させることが3D印刷の表面品質を高める鍵であると結論づけます。

Keywords

💡quality printing

Quality printing refers to the process of achieving high-quality surface finishes on 3D printed objects. In the context of the video, it is defined by the precise extrusion of plastic at the right location and time. The video discusses the challenges in achieving consistent surface quality, especially with high-end machines, and explores the factors that can lead to imperfections such as layer stacking and irregular surfaces.

💡layer stacking

Layer stacking is a visual artifact that occurs in 3D printing when the layers of plastic are not properly aligned or fused, leading to a rough or uneven surface appearance. It is a critical issue addressed in the video, as it directly affects the aesthetics and sometimes the structural integrity of the printed parts.

💡pressure advance

Pressure advance is a feature in 3D printing software that helps synchronize the extrusion of filament with the printer's movement. It ensures that the correct amount of plastic is extruded during starts, stops, and cornering. In the video, the speaker discusses how pressure advance might not be the cause of the surface quality issues they are experiencing due to the use of vase mode, which has a continuous and steady extrusion flow.

💡Z wobble

Z wobble refers to the lateral movement or instability of the print bed along the Z-axis during printing. This can cause horizontal artifacts in the printed object and is usually a result of misaligned or crooked lead screws. The video script mentions Z wobble as a potential cause of the irregular surface patterns, but the speaker rules it out based on the behavior of the pattern distance changing with the size of the printed part.

💡extruder system

The extruder system is a critical component of a 3D printer responsible for feeding the filament into the hot end where it is melted and deposited onto the build platform. The video delves deep into the mechanics of the extruder system, discussing its various parts and their impact on print quality. Issues with the extruder system can lead to inconsistencies in the amount of plastic being extruded, affecting the surface finish of the print.

💡Bowden setup

A Bowden setup in 3D printing refers to a configuration where the extruder motor and the filament path are separated from the hot end. This setup often results in smoother prints due to the dampening effect of the longer tube that reduces vibrations and pressure fluctuations. The video highlights the author's positive experience with a Bowden setup and how it led to better print quality compared to direct drive extruders.

💡manufacturing tolerances

Manufacturing tolerances are the allowable variations in the dimensions and specifications of a manufactured part. In the context of 3D printing, tolerances in the extruder system components and the filament can affect the precision of extrusion, leading to variations in layer width and surface quality. The video emphasizes the importance of tight manufacturing tolerances for achieving high-quality prints.

💡flow variation

Flow variation refers to changes in the rate at which filament is extruded by the 3D printer. Inconsistent flow can lead to uneven layers and surface artifacts in the printed object. The video uses the concept of flow variation to explain how slight changes in the extrusion process can significantly impact the print quality.

💡direct drive extruder

A direct drive extruder is a type of extruder where the motor is in direct contact with the filament, driving it directly without the use of a Bowden tube. While this setup can offer certain advantages, the video highlights that it can also make the printer more sensitive to manufacturing defects and variations, as there is no dampening effect to smooth out inconsistencies.

💡radial runout

Radial runout is a term used to describe the deviation of a rotating part from its true rotational center. In 3D printers, radial runout in the extruder gears can lead to inconsistent extrusion, as it causes variations in the amount of plastic being pushed through the hot end. The video emphasizes the importance of minimizing radial runout to achieve consistent and high-quality prints.

💡surface quality

Surface quality refers to the smoothness, uniformity, and overall appearance of the outer surface of a 3D printed object. High surface quality is often desired for aesthetic or functional reasons, and it is greatly influenced by the precision of the extrusion process and the printer's mechanical stability. The entire video is dedicated to exploring the factors that affect surface quality in 3D printing and potential solutions to improve it.

Highlights

The core principle of quality printing is the precise delivery of plastic to the correct location at the right time.

High-end machines sometimes struggle to match the print surface quality of a Prusa or well-tuned Ender 3.

The presenter aims to reveal the truth about high-end printers and the role of luck in achieving good wall surface quality.

The timing of the print is managed by the software, extruder motor, and the synchronization of X and Y movements.

Pressure advance ensures the correct amount of plastic is available during starts, stops, and cornering.

The presenter questions the role of timing in surface quality issues, as it is not the focus of the day's investigation.

Nozzle positioning on the heater bed is crucial and should be carefully aligned and stable to avoid artifacts.

Z-wobble can cause horizontal artifacts but is unlikely to be the cause if the pattern distance varies with part size.

The extruder system is broken down into elements to pinpoint the root cause of surface quality issues.

The stepper driver, motor, and hot end are ruled out as causes due to their consistent performance in a Bowden setup.

A BMG clone extruder gear assembly produced better results, indicating the importance of gear quality.

Manufacturing tolerances can affect the position of the hub gear on its shaft, leading to uneven extrusion.

A simulation is run to demonstrate the impact of gear runout on the extrusion process and print quality.

The extruder should be considered a precision instrument, and better components are needed for direct drive machines.

Filament quality and consistency also play a significant role in the extrusion process and final print quality.

A revised gear assembly that combines the shaft and hub gear as one part is developed to reduce runout.

After testing various components, the idler gear is identified as the likely source of the persistent artifact.

Replacing the idler gear with plane bearings eliminates the artifact, indicating the importance of maintaining proper alignment.

The presenter concludes that a more precise extruder system directly translates to better surface quality.

Transcripts

the theory behind quality printing is

fairly simple

the right amount of plastic to the right

location at the right time

this sounds easy

so tell me why is it that we struggle so

much with our high-end machines to

achieve the same print surface quality

as a prusa or a well-tuned Ender 3.

every picture or video showcasing

printed Parts on the internet will make

use of a soft light coming from the side

to make your part look good

very rarely do we see these prints under

a sharp light coming from the top

in this video I will be using the worst

lighting conditions for fdm printing

ever

be ready to see some very ugly layer

stacking

I think it is one of the biggest Untold

Truth About a lot of high-end printers

until now luck has been playing a huge

role into your printer's ability to

produce nice wall surface quality

I may receive rocks for making this

comment but I can tell you that this was

the case for my printer as well until

now

today we will find the answers to your

surface quality issues once for good

what could be the cause of this artifact

sometimes horizontal or at angle other

times creating irregular surfaces let's

try to isolate which of these three

elements could be responsible

the timing portion of the print is

managed via the software extruder motor

needs to be in perfect sync with X and Y

movements the pressure Advanced function

will ensure that the right amount of

plastic is available for starts stops

and during cornering

since I used vase mode for this cylinder

pressure Advance would not have much

impact because there is no stop and go

it is a continuous and steady Extrusion

flow

therefore I don't think timing is

involved in what we're looking for today

the next probable cause is the

positioning of the nozzle on the havort

I took extra care about the location

alignment and stability of the X and Y

Gantry during design

by selected Quality Parts and validated

the installation at every step

the typical artifact from a defective X

or y-axis would repeat itself at the

same spot for each layer this would

eventually create a vertical pattern

that we don't see right here

and horizontal artifact could be related

to Z Wubble

on a core x y z wobbling is usually

caused by the lateral movement of the

print bed due to misaligned or crooked

lead screws

you can see my previous video on the

topic right here

the triple z-mounted on both screws for

this printer is the part that gave me

the most challenges

but I have reached my goal with the

wobble X isolators

thanks to my good friend Oleg for coming

up with this idea

you will see more on this solution in a

future video so make sure to subscribe

and activate the notification button so

you don't miss any of that

the issue I'm looking at right now has a

weird Behavior the pattern distance will

vary if I change the size of the part

being printed therefore chances that it

is the result of z-wobbling are very

slim

Z wobbling would be constant no matter

what I print the same distance between

each artifact would repeat across the

print

so if it is not X or Y

if it is not Z

and if it is not the timing

this leaves us with the amount of

plastic being extruded

really

but you're going to tell me my extruder

was perfectly calibrated using the 120

and 100 millimeter technique and then

with the single wall Cube to calibrate

the flow multiplying Factor

I've even performed PID tuning of the

hot and eater with cooling fan on and

filament extruding how can this be

related to extruding system

I never thought of deep diving into

extruders until I made a Bowden adapter

for my printer

Magic

the nicest print I ever produced

appeared in front of my eyes at the

first use of this Bowden setup

why is Bowden producing such nice prints

could it be that our very short path

direct drives extruders are in fact too

much Direct

could the dampening effect of the Bowden

tube and the filament compression on all

that length contribute to stabilize the

pressure inside the nozzle

I like printing fast and you know it

but the length of the tube required from

my printer size made the retraction and

pressure at best to slow things down by

a way work

so slow that I could not live with this

what could I do to smoothen the extruder

system without using this long tube so

let's break the extruder system into

elements so we can properly pinpoint to

the right root cause

it all starts with the stepper driver

providing inputs to the stepper motor

with the help of its pinion gear the

stepper motor will then drive the

extruder plastic gear that is connected

to the shaft

holding the extruder gear itself

that extruder gear is then providing

power to The Idler gear via the gear

teeth at the end

both gears are then squeezing the

filament and pushing it downwards into

the hot end

this sounds like a very simple system

but I think we can shorten that list

even more

so just remember for my Bowden print

that looked so good before I was using

the same filament the same hot end the

same stepper driver and the same motor

so let's remove them from the equation

for now

with a methodical approach I printed the

same G-Code while changing only one

parameter at the time

this allowed me to eliminate many things

that had no significant impact on the

surface quality

it was not due to microstepping not due

to motor current not due to the motor

itself not to backlash between the motor

pinion and the drive gear not the

meshing of The Idler gear yeah you

probably think that this has to do

something but trust me I even went and

grinded the teeth off of one of my idler

gear to test that one

no impact

I then swap to another extruder gear

assembly one that came into a BMG clone

that I had in stock

surprise

the results were much better I still had

a bit of that artifact but overall the

texture was way smoother

we are getting closer I feel

looking at the BMG gear carefully I

realized that the Hub gear could get out

of axis the thing is that the current

design allows for the manufacturing

tolerances to affect the position of the

Hub gear on its shaft

if tolerances for the gear inside

diameter are at the maximum and the ones

for the shaft at the minimum

the set screw will be able to pull the

Hub gear out of its rotation Center

the gear will now be rotating in a

manner where we get more plastic on half

of the rotation and less on the other

half of the rotation

we could picture the flow variation as a

sine wave

you can try printing a 30 millimeter

single wall cylinder like this one and

then change the timing of this sine wave

by increasing the Extrusion flow or

reducing it as you are printing

see how the artifact pattern is

completely changing with flow variation

on this tube

to quantify the flow variation I

measured the amount of run out of the

Hub gear of my BMG units and noticed a

slight amount of the aviation

but how much is too much

can I run out of three thou of an inch

create such an artifact

yeah okay I know inches here in Canada

we mix both systems

I drive at 100 kilometers an hour but I

am six foot one tall

anyways because 3D printing is using the

good system

let's convert that 3000 inch into

something more meaningful

three thou of an inch multiplied by 25.4

millimeter per inch gives us 76.2

microns that still does not sound like a

whole lot to me

but what does that really mean when we

print

let's run a little simulation

our gear has a diameter at the Hub of

7.2 millimeter if we offset that gear by

half of that total run out that we

measured before we are going to shift it

to one side by 38.1 microns the gear

assembly will now act as a 7.276

millimeter Hub gear when that side

reaches the filament

then when the opposite side gets to the

filament

the effective diameter of our extruder

becomes

7.124 millimeter

so a total oscillation of 152 microns

now we can start to feel the impact of

this situation in theory if our gear was

perfectly Centered for every millimeter

of extruded filament we would get 2.405

cubic millimeter of plastic

but because our gear is tricking us we

will sometimes get more plastic and

other times we will get less

when the Hub gear is shifted towards the

filament The Hub gear will pretend to

have a diameter of 7.276 millimeter

therefore being 1.05 percent bigger than

the perfect 7.2 we had earlier

and because of that augmentation we are

not getting the requested 2.405 cubic

millimeter of plastic anymore

we are getting 2.43 cubic millimeter

on the other hand we are only getting

2.38 cubic millimeter of plastic when

the Hub gear is shifted at the opposite

side of the filament and therefore

pretending to be only 98.94 of the real

thing

between the two scenarios we now have a

total difference of 0.05 cubic

millimeter of plastic and this is for

only a length of one millimeter of

filament extruded okay I give it to you

we are back with small numbers again but

bear with me for a moment if we were to

take that theoretical 2.405 cubic

millimeter of plastic from our perfect

gear and shape it into a 0.5 millimeter

wide by 0.1 millimeter thick layer

profile it would have to be 48.1

millimeter long

where am I going with this

remember your mom's cake icing bag or

that silicone caulking gun you used the

last time redoing the shower seal

what would happen if you apply that

icing or caulking at constant speed

while maintaining a nice and even layer

thickness but you keep varying the flow

you guessed right you're not going to

push yourself into going faster and

neither will you go higher only that

nice Extrusion bead is now going to be

wider I prepared that little 3D model to

show the difference between the lean

layers and the over extruded ones from

our previous example the under extruded

lines have now a width of 495 microns

the over extruded ones on the other hand

have expanded to 505 microns although

this is only a variation of 10 microns

we can clearly see on this model the

impact on the surface quality

this is an eye-opener for me the

extruder should be considered as a

Precision instrument

we need better components for our direct

drive race machines

the level of precision on the quantity

of material extruded is also directly

impacted by the manufacturing tolerances

of your filament if we use the same

simulation Model A variation of plus or

minus 0.05 millimeter on the filament

diameter could mean a layer width

varying between 0.47 millimeter wide and

0.53 millimeter this is huge but usually

this variation will be spread over a

greater distance of filament but this is

something to keep in mind look at this

weird spiral caused by the poor quality

from the end of a spool that I had in

stock

if you wish to up your print quality

game it is therefore important that you

choose a filament manufacturer with

pretty tight tolerances

the work involved in making this video

started back in August a lot of work

material components and time has been

invested my patrons were able to read a

weekly report on my findings during this

journey dear patrons thank you very much

you are covering a portion of the costs

involved at producing these kinds of

research if you two would like to help

me out and would like to benefit from

the detailed insights about my

experiments I invite you to visit my

patreon page by clicking on the address

link here Below in the video description

over and above the support from my

patrons I also benefit from a huge moral

support from my good friend VES 3D

well perhaps he is not the best to

provide any kind of moral advice with

his lack of self-discipline but I do

appreciate our long scientific

discussions and his large sense of drama

I like what Simo does with his visibot

nah seriously man thank you very much

for allowing me to bounce ideas on you

and for keeping me focused when I get

discouraged thank you brother

understanding the considerable variation

that such a radial runout would give I

approached bontech and explained the

situation earlier this year they've been

super responsive from the start and we

then worked on a revised gear assembly

that would combine the shaft and the Hub

gear as one single part therefore

removing chances of having a hub gear

out of Center

after a few months of wait I was very

excited to try these new gears on

if this works we will be able to

maintain our tiny direct drive's

extruders and get much better quality

with a little over 5 10 of a thou

yeah oops sorry inches again

12.7 microns should I say of run out

these shafts should be much better

well nothing in life is easy I am

getting the same artifact once again a

little less pronounced but it is

definitely still there

just like a ton of brick in the forehead

it hit me

what about the plastic gear

oh my God it was such a downer to

realize that I was focusing on the metal

gear while the plastic gear was just as

bad if not much worse

in some cases reaching up to 152.4

microns of run out so I had to try

pressing on my best plastic gear coming

from the BMG clone unit that I had onto

that new shaft from bontec

ah [ __ ] some days are better than others

that was not the case for today

I will sleep on it

while in bed I started to shop around

for better drive gears could we get some

machine gears pressed on should I

completely change my extruder design

just as I was ready to close my eyes

this thing appeared physic just released

a new improved gear

better Precision apparently seems to be

a machined plastic gear oh well let's

order a few

four weeks have passed and here we are

the new gears have arrived

how precise are they

well they are not perfect but with just

under 50 microns of run out this is by

far the best units I've seen let's try

to press it on the shaft but this time

around I will preheat the shaft before

trying to press it in

foreign

[Music]

there it is

it looks very good and I was able to

maintain the initial run out tolerances

intact for both the plastic gear

and the hot gear

and now let's print

so right now I could teach you a few

swear words in French Canadian

because let me tell you I've used a lot

of them so new shaft more precise New

Gear more precise

looks a bit better but it is not what

I'm expecting

there is definitely something else going

on there what is that artifact once

again changing flow of the extruder

would change the pattern it is

definitely related to the extruder

Could It Be The Idler Hub at this point

even if I don't have any logical theory

about it let's try to swap it and

replace the idler Hub gear for a stack

of plane bearings I may get less

traction but at this point I could not

care less

oh wow it is gone but why what is going

on why is that artifact gone

so The Idler gear seems to hold the

answers to our questions so here's my

theory

if the idler gear shaft is slightly

tilted

and it wouldn't take much as we've seen

earlier with very small numbers having

noticeable impact on the surface quality

this tilt could apply a force at angle

on the filament this means that the

filament could be pushed forward or

backward and therefore changing its

position inside the Hub gear Groove

changing position in the groove would

also mean changing the effective

extruding diameter of the Hub gear using

our cat simulation model we can see how

much impact can this condition where the

filament is Walking In the Groove have

on the print surface

it can definitely throw things off by a

much greater margin than our 76 Micron

Hub gear run out hand look at that

incredible

the design of my tiny extrudort could be

in cause for not maintaining The Idler

shaft parallel properly to the drive

gear the limited amount of actual

backlash on The Idler might not allow

for a perfect self-alignment of that Hub

Group

print accuracy of the extruder body

could also play a role many factors need

to be perfectly under control for an

extruder gear system like the BMG to

work properly now that I know the source

of this annoying artifact I can retest

properly The Hub gear shaft assemblies I

have in stock using an idler made from

bearings the first one on the left was

done with the bontecht original extruder

gear shaft assembly

we can clearly observe the Ripple

artifact from the extrator gear wobbling

around its axis

in the middle comes the new shaft

assembly that I made from the bontec new

experimental integrated shaft and the

plastic gear from physet the repetitive

Rippling is practically gone although a

few artifacts are still showing up the

quality is much better

and on the right I reprinted a tube

using my Hamera in Bowden mode to

compare although it is still the best

tube from the three I think the results

obtained with my revised direct drive

configuration is pretty close to what

Bowden gives we have to remember that

this observation is being done with the

light coming from the top and every

little variation in flow will show up

either caused by pid heater pulses

filament homogeneity filament diameter

nevertheless it is clear to me that the

more precise your extruder system will

be the better surface quality you'll get

I'm currently having discussions with

montec for a potential solution to be

offered that would help those of us with

a compact direct drive extruder based on

the BMG internals I'll keep you guys

posted when something is ready

in summary the last two months have

thought me a lot in what is going on

into the extruders they are probably the

most important part of a 3D printer

their impact is also Amplified if you're

using them into a direct drive extruder

because we're not benefiting from the

dampening effect of a Bowden tube every

single little defect or variation will

directly be translated to your print and

as explained today it does not take much

to create visual artifacts

I hope this video can help you to

increase your print quality let me know

in the comment section below what was

the mod that had the best impact on your

print quality

now that you have seen me naked with all

my defects let's get dressed let's put

back on this very nice light dress that

makes us shine under our best angle for

the photo

see you soon happy printing