Food24

Hello all, this is Food24, a researcher that recently is paying attention on the employment of 3D printing for food manufacturing. I and my research group have about 3 years of experience in the creation of 3D printed edible objects. This is a very interesting technology that many companies are trying to use for food personalization. Although I have performed several experiments modulating variables such as speed printing, travel speed, flow, layer height, etc., gnerally we have some discrepancies due to the fact that the software are optimized for thermoplastic materials and nothing is for food which have many differences in mechanical properties (viscosity, adhesivity, flowability, etc.). One of the most important problem are oozing and stringing created during printing and non printing movements. But these are ahard to solve by tuning rectraction, etc. I'm very interested - and I want to ask anyone - if there are some software that we can use to design the path of printers in the way to avoid some specific movements creating defects. I read something use the software FILOU NC 16 but i was not capable to find it. May you suggest me software by which I can 'literally' design the movement of the printer? All the best, Food 24.

Dear ahoeben, something is not clear yet. Are the values about how fast my printer accelerates/decelerates while moving, defined by my firmware? What do you mean when speak about ' mismatch between your printer firmware and the default values that Cura has to use when the printer definition does not include values about how fast your printer accelerates/decelerates while moving' ? I known that the installed firmware contains the parameter by which the printer will move. By using CURA we only define most printing parameters which are contrained by acceleration/deceleration, jerk etc as defined in firmware. Also, i would like to understand if CURA well define the movement of a DELTA printer or some bugs could be between the estimated movement and the actual one. Thanks Food24

Dear All, my question today is on the estimated printing time by CURA. I have printed a small pyramid with a base of 29*29 mm and an height of 22 mm. The estimated time by CURA is about 4 minutes. My printer finished to print after 2 min and 40 s. It is possible that CURA has some bugs which produce this type of error ? I have this problem when i print at very low print speed of 11.21 mm/s while when I print at 16 mm/s and 21 mm/s the estimated time are close and lower than the actual times, respectively. Maybe there are values of minimum Feed Rate at which the printer cannot move ? From the display of my printer (a Delta Wasp 2040) i read this setting conditions Vmax(x,y,z,e) 250 250 250 60 Vmin 0 Vtravel min 0 Amax(x,y,z,e) 20000 20000 9000 3000 Vx,y_jerk 20 Ve_jerk 5 Accelleration 3000 A_retract (e) 3000 - - - Estep(x,y,z,e) 85.33 85.33 85.33 400 Food24

Dear all, I'm a little confused on the information about E-step. On Marlin I can find that: 1. the default steps per mm are 80,90,4000,500 for X,Y,Z, E0 respectively. 2. the default Max Feed-rates are 500,500,2.5,45 for X,Y,Z;E0, respectively. It is not clear for me the difference between the two information. How is possible that the default values for E-axis is greater than its maximum rate ? Can you explain me what exactly means these two information ? Thanks Food 24

Dear all, on Marlin, the default step for unit in E-axis is 500 which should be 500 step for minute corresponding to 8.3 step per second to move. Is it correct ? Also i found on CURA Manual that should be to keep the E-step at 0 meaning that in this condition I sue the default value of 500. But what's happed if i insert on CURA a E-step of 400. In this case i reduce the E-step value or i'm increasing it of 400% ? Please explain me differences between E-step value on marlin and the values indicated on CURA. Thanks Food 24

Dear all, I'm using a printer Wasp mod. Delta 2040 equipped with clay extruder. Also, Marlin firmware. As reported in the firmware, the default values for X,Y,Z,E axes are: * D e f a u l t A x i s S t e p s P e r U n i t ( s t e p s / m m ) * O v e r r i d e w i t h M 9 2 * X , Y , Z , E 0 [ , E 1 [ , E 2 [ , E 3 ] ] ] * / #define DEFAULT_AXIS_STEPS_PER_UNIT { 80, 80, 4000, 500 } my questions are below: 7 1. The value 500 is on mm/min. if so, the acutal value should be 8.33 step/mm of filament in a time of 1 s. 2. If I leave on CURA software an -Estep=0 this means that i'm using the default value of the firmware that is 4000 ? 2. What's happen if i change the E-step value on CURA software for instance at +0400 ? Can you help to explain me exactly how change the E-step when I modify it on CURA software ? Thanks Food 24

I all, i'm using a printer WASP delta 2040 equipped with a clay extruder kit. Also, I'm trying to pring food like dough, vegetable cream, etc. I'm using Marlin firmware. Since i have some doubt about estimated and acutal printing time, i reported below the setting of my printer that i can read from the display of the printer. ACC=3000 (should be 50 mm/s) Vx,y= 20 mm/s Ve= 5 mm/s (should be the default velocity of E-axis); Vmax (x,y,z,E)= 250,250,250,60 Amax(x,y,z,E)=20000,20000,20000,9000,3000 Aretract=3000 (should be default acceleration of retraction) xstep/mm(x,y,z)=+085.33 estep/mm=+0400.0 What you think about this setting ? something is wrong ? In practice in some conditions i have from cura an estimated time of 4 min while the actual time 3 min. How can i explain this ? Thanks Food24

I'm using a printer WASP, mod. Delta 2040 . I use Marlin firmware. Also my object is a n.10 faces-pyramid with a base of 29x29 mm and an height of 22 mm. Something is not clear for me: The jerk specifies the istantaneous rate reached from the printer before acceleration. Practically, jerk works when chaging speed or direction. If the jer is 20mm/s and i'm working with a speed rate of 11.2 mm/s this means that the printer istantaneously reach 20 mm/s. If so there are two possibilities: 1. the printer decelerates from 20 to 11.2 mm/s; 2. the printer will move faster than expected behaviour. In my test when I print at 11.2 mm/s I have an actual printing time of 152 s while the estimated time is of 240s. What could be the reason ? Food24

Hi all, usually estimated time from CURA is greater than the actual time due to ecceleration and jerk factor. But, it is possible the contrary ? it is possible that actual time is lower than the estimated one ? For instance if jerk is 20 mm/s (default acceleration is 50 mm/s) and i'm printing at print speed of 11 mm/s, could be possible that my printer moves faster than the estimated behaviour ? Thank all. FOod 24

I have additional doubt: considering the above reported equation: V=pi*radius^2*print speed = mm3/s. But i believe that It is correct only if we are using a flow rate of 100% (by using CURA). It is because if we use a flow of 120%, the volume of deposited material (not of the printed object) should be greater than the 20% ? Vcorrect=V+V*0.20 ? (Eq.2) Similarly if we use a flow of 70% the V=V-V*0.30 ? (Eq.3) What you think ? Food24

Dear all, i have a question very difficult for me: It is possible that by changing some printing variables such as (but not only) print speed (feed rate) a different path of the printer is planned by firmware Marlin ?. If so, should be possible that this takes more time for printing. My question arise from some results that i obtained in the last days. Particulary, I obtained total (measured) printing time of 150 s, 180 s and 150 s by using print speed of 11, 16 and 21 mm/s. If the setting of other variables are exactly the same i cannot explain this. So, would be possible that at print speed of 16 mm/s a different path is obtained producing an increase of printing time. Can anyone help me to explain this observation ? Thanks Food 24

Dear gr5, just a couple of questions on the basis of you explanation: if the first your response you told me: 'When you increase flow it increases the amount the extruder moves: FOR ALL MOVES'. Then, in your second comment, you stated that 'Flow should only affect the E axes'. I'm confused about it. When I increase print speed (feed rate) i increase both X,Y,Z rate and E axis rate because it is necessary more material vs time. Similarly, when i increase flow rate (E-axis) i also incrase the X,Y,Z rate to make possible a good deposition. But are these two case the same? Let me assume that i increase the speed rate from 10 mm/s to 20 mm/2 (twice) and that the E-axis increase also of two time. If so, the new equilibrium should allow to mantain the deposition rate (amount of material extruded for second) constant because all axes incrased in twice. Contrarly, if i increase the flow of 200% i should see an increase of print speed in X,Y,Z axis from 10mm/s to 20 mm/s. Going to my question: If i increase speed of X;Y,Z axes of 100% (or 50%) i should be see an increase of E-axis of the same amount (100% or 50%)? and similar result should be obtained if i increase the flow of 50% or 100% (obtaining an increase in X,Y,Z axes of 50% or 100%). Thanks Food24

Dear Tomnagel, you consideration are correct and very useful for me. But i'm printing food (vegetable cream) and not plastic filament. My interest is just to calculate the amount (volume) of material (food) deposited during printing while i have not interest in the total volume of the 3D printed object. Also, let me assume that is not our interest to have a good printing (a good 3D printed object). I known that by printing on air i have a volume of material greater than the 'real' volume of the printed object. This is because, as you well reported, extruded plastic (or extruded food ) is pushed onto the previous layer producing a modification of its shape (from cylinder to rectangular shape). But back on the theory, my question is to precisely calculate the amount (volume) of material extruded by considering the nozzle size and print speed as follow. Since the filament (when extruding) have a shape of cylinder the correct total volume of material should be: V=pi*radius^2*print speed = mm3/s. Again, obviously this isn't the volume of the printed object because each layer will be squashed between other two layers but, in my opinion, is the correct amount of material estruded through the nozzle thata was necessary to built our 3D object. What you think on my consideration ? Food24

Thank Tomnagel, but if I'm using a clay extruder with a nozzle having a round shape, i cannot consider a rectangular shape. In this case the second equation should be more precise because I have ha cylinder. Also, In my opinion the equation should works also if I'm printing not in air. What is the difference if i'm printing a more o less perfect cylinder on air or if this cylinder is used to build a 3D object ? Briefly, even if after printing the cylider changes is shape, the amount (volume) of printed material should be the same. Of course the 3D object will have a different volume than the printed material. Thanks Food24.

Dear all, i found that it is possible to calculate the flow rate (FR) by the following equation: FR = Nozzle size (mm) x layer height (mm) x print speed (mm/s) = mm3/s. Nevertheless, it is not clear because of in this equation the surface of the filament it is not taken into account. In general if I work with a nozzle of 0.5 mm and a layer eight of 0.4 the minimum volume (MV) of filament needed is: MV = pi*radius^2*height = 3.14*0.25^2*0.4 = 0.0785 mm3. Let me assume that i'm using a print speed of 30 mm/s and that i'm printing on air obtaining a filament (cylinder) of height = 30 mm for each second of printing. So, in this way i'm printing a volume of V=pi*radius^2*height = 3.14*0.25^2*30 = 5.88 mm3 that is a flow rate (FR) of 5.88 mm3/s. May you help me to correct above consideration ? Thanks.