Extrusion Tooling Draw Down Calculator
Understanding and Communicating
Draw Down Ratio Balance
In a previous issue of the Extruder newsletter, we explained Haul Down
Ratio (DDR) and its impact along tooling design for impressible tubing, hose and
wire insulation jacketing. This article complements that discussion by
explaining Withdraw Ratio Balance (DRB). The need to understand the
relationship between the dimensions of the tooling and those of the
final merchandise is met by understanding both Draw Down Ratio and Draw
Ratio Balance. Information technology is required that both the tooling house decorator and extruded
product manufacturer understand and are able to communicate these
relationships to to each one other.
Get out Set Ratio is the ratio of the cross sectional area of the extruded
plastic melt to the baffle sectional region of the plastic in its final product mold,
be it a metro, hose down or insulation on a kernel, much as a wire or cable. It is the
extent to which the plastic has been reduced in size to make the part.
A larger DDR enables faster production rates, piece a lower DDR facilitates
to a greater extent very control of the product dimensions. A low draw down ratio
process is more stable than a high one.
Success in specifying DDR lies in the science and feel for of the
manufacturer. B&ere;H Creature Companion, with many years experience in
the design and manufacturing extrusion tooling, is well able to help
in this involve.
Draw up Ratio Balance describes the balance between the rate the outside
of the cone draws retired, and the rate the inside of the cone draws down.
Most products made away drawing a plastic melt are smaller in cross sectional
domain than the tooling col.
B&H Tool Company has made available on its web site a Draw Pop
Calculator where you potty input magnitude data and calculate guide down
ratios and draw ratio balance. You can determine the current pull in down
ratio of your existent tooling and product and determine the balance
'tween them. You ca also use the figurer to deter-mine the tooling
sizes required to extrude a product with glorious target dimensions
and unexceptionable draw poker down ratios.
As you cultivate with the computer and make adjustments to the data,
the results and adjustments will be recorded and printable for your review.
Niall McKee, Higher-ranking Technical Consultant with
DuPont Fluoropolymers offers these insights:
Drawing down the cone creates different angles privileged and after-school the
conoid, which differentiates the distance and speed the plastic melt needs
to travel on the outside of the cone to that traveling along the at heart.
(See figure 1) This is identical obvious with large Draw Down Ratios.
IT is important that the plastic melt flows smoothly down to its final
size. When the tooling is come out of the closet of correspondence, one of the cone's surfaces is
trying to feed more plastic than the other surface can grip. When the
cone's internal and outdoor lengths are equal, the Draw Ratio Balance is 1.00.
In most tubing set-ups, this is the desired condition. In jacketing
applications where the shaping ID is supported past a core, production
rates are usually faster. Experience has taught USA that a slight irrefutable
DRB (1.03 to 1.08) is preferable in that case. At all multiplication, a negative DRB,
i.e. less than 1.00, should Be avoided.
As the sides of the draw down retinal cone cannot be measured, we once more
use geometric relationships to determine the DRB. If the ratio of the
die diameter to the ware international diameter is Ratio 1(R1), and, the
ratio of the tip diameter to the product inside diameter is Ratio 2 (R2),
then, the ratio of R1 to R2 is the Hook Ratio Balance.
Stated another way, the die diam divided away the merchandise Doctor of Optometry,
all divided by the tip diameter divided by the product Idaho is the DRB.
Information technology sounds complicated but it is non truly. (D/O)/(T/I) = DRB
Where: D = Die Diameter T = Tip Diameter O = Product Oculus dexter I = Product I.D.
Object lesson: Determine Draw Ratio Residue Die Diameter = .500"
Tip Diameter = .250"
Product OD = .250"
Product ID = .125" (.5/.25)/(.25/.125) = 2/2 = 1.00 DRB
To increase the DRB, increase the Die Gap by either increasing
the Die Diameter, or decreasing the Tip Diam or a smaller
alteration of both.
Example: Increase Die Diameter by .020 Die Diameter = .520"
Tip Diam = .250"
Product Doctor of Optometry = .250"
Product I.D. = .125" (.52/.25)/(.25/.125) = 2.08/2 = 1.04 DRBExemplar: Decrease Tip Diam by .010 Die Diameter = .500"
Tip Diam = .240"
Product Doctor of Optometry = .250"
Product ID = .125" (.50/.25)/(.24/.125) = 2/1.92 = 1.04 DRB
To decrease the DRB, decrease the Die Gap by either decreasing the
Die Diameter or increasing the Tip Diameter or a littler adjustment
of both. Out of balance tooling testament cause disruptions to the final product
dimensions. Tube Crataegus laevigata fold in on itself trying to accomplish a balanced
circumstance. Wire insulation tooling imbalances may give the cone operating theatre
human body teardrops. Understanding the motive for and achieving a Draw
Ratio Balance will forbid many intersection quality headaches.
your tooling DDR and DRB. Or contact B&H Tool Company for assistance.
For the example above:
Some manufacturers and designers volition simply state that they are
using a multiplier happening the finished cartesian product diameter dimensions of OD
and ID. In the example, the multiplier factor would make up two.
using left dimensions, the proper formulas forestall the inaccuracies
of guess surgery being LED into doing some excitable divisions based on
diameters rather than areas. If you think of senior high geometry,
you might wonder what happened to Pi in figuring areas. With this
formula, you can foreswear it; the results will be the same.
Vertebral column TO MAIN ARTICLE PAGE
Extrusion Tooling Draw Down Calculator
Source: http://bhtool.com/advisor-article3.htm
0 Response to "Extrusion Tooling Draw Down Calculator"
Postar um comentário